Digital domain content processing and distribution apparatus and methods

ABSTRACT

Methods and apparatus for distributing content using a spectrum generation device. In one embodiment, digital content is received via a time-multiplexed network transport (such as Gigabit Ethernet), and converted to frequency channels suitable for transmission over a content distribution (e.g., Hybrid Fiber Coaxial (HFC)) network. In one variant, the conversion is performed using digital domain processing performed by a full spectrum generation device. Additionally, methods and apparatus for selectively adding, removing, and/or changing digital content from the full spectrum device are also disclosed. Various aspects of the present invention enable physical (infrastructure) consolidation, and software-implemented remote management of content distribution.

PRIORITY AND RELATED APPLICATIONS

This application is a divisional of and claims priority to co-owned andco-pending U.S. patent application Ser. No. 12/875,974 of the same titlefiled Sep. 3, 2010, and issuing as U.S. Pat. No. 9,185,341 on Nov. 10,2015, which is incorporated herein by reference in its entirety. Inaddition, this application is related to commonly owned U.S. patentapplication Ser. No. 12/789,322 filed May 27, 2010 and entitled “DIGITALDOMAIN CONTENT PROCESSING AND DISTRIBUTION APPARATUS AND METHODS”,incorporated herein by reference in its entirety.

COPYRIGHT

A portion of the disclosure of this patent document contains materialthat is subject to copyright protection. The copyright owner has noobjection to the facsimile reproduction by anyone of the patent documentor the patent disclosure, as it appears in the Patent and TrademarkOffice patent files or records, but otherwise reserves all copyrightrights whatsoever.

BACKGROUND OF THE INVENTION

1. Field of Invention

The present invention relates generally to the field of optimizing theoperation of a content delivery network. More particularly, the presentinvention is in one exemplary aspect related to apparatus and methodsfor providing adaptive network routing.

2. Description of Related Technology

Recent advances in digital information processing and technology havemade a whole range of services and functions available for delivery toconsumers at various types of devices for reasonable prices and/orsubscription fees. These services and functions include digital contentor programming (movies, advertisements, etc.), digital video-on-demand(VOD), personal video recorder (PVR) and networked PVR (nPVR), InternetProtocol television (IPTV), digital media playback and recording, aswell high speed Internet access (including so-called “Internet TV”,where television programming is delivered over the Internet without QoS)and IP-based telephony (e.g., VoIP).

Currently, many of these services are provided to the user via a widevariety of different equipment environments and delivery paradigms(including, inter alia, cable or satellite modems via QAMs, HybridFiber-copper (HFCu) distribution via indigenous POST/PSTN wiring in apremises, Wi-Fi™ or WiMAX hubs, Ethernet hubs, gateways, switches, androuters), to a plurality of user equipment types. For example, contentmay be delivered to users at set-top boxes, personal (desktop)computers, laptop computers, other mini-computers (such as so-called“netbooks”, mini-notebook computers), 3G or 4G smartphones, and/or otherdevices.

Traditional cable network delivery services are optimized forbroadcasting a limited number of services to a much larger audience ofconsumers. Cable networks compete with other systems, such as satellitebroadcast and HFCu service. Within cable networks, so-called“narrowcast” content is provided for a relatively small number oftargeted consumers. In a broad sense, narrowcast content is content (orits associated bandwidth) that is more narrowly distributed to a subsetof the subscriber pool serviced by a given network. Examples ofnarrowcast content include VOD, “startover” functionality, DOCSIS, andswitched digital video delivery. Narrowcast applications (such asadvertising, data, premium content, etc.) generally have greater valuefor the consumer, and are a source of significant revenue for networkproviders. Additionally, narrowcast applications have traditionally beenone key differentiation between cable network providers and theircompetitors (e.g., satellite service).

However, while narrowcast content has significant business value, thetechnical realization of narrowcast content insertion (includingso-called “targeted” content, such as targeted advertising orpromotions) greatly complicates cable network topologies and operation.

Originally, cable networks were carefully planned around relativelystatic parameters; for example, analog delivery of channels operatedusing fixed frequencies and time slots. As cable networks havetransitioned to digital content and narrowcast services (such asSwitched Digital Video (SDV) and Video-On-Demand (VOD)), additionalinfrastructure has been added to support splicing, mixing, etc. withinthe existing analog delivery framework. Current cable networks are oftena less-than-coherent mix of somewhat haphazardly organized equipment.Worse still, a growing maze of wiring and cabling connects clusters ofspecialized hardware which further exacerbates network managementchallenges. Typical cable network infrastructure is often both hard tomaintain and modify, and increasingly difficult to upgrade. Asnarrowcast services continue to diversify and drive increasing portionsof business revenue, the demands on network infrastructure may rapidlyexceed sustainable limits.

FIG. 1 illustrates one such prior art content delivery networkconfiguration. The various components of the network 100 include (i) oneor more data and application origination points 102; (ii) one or morecontent sources 103, (iii) one or more application distribution servers104; (iv) one or more VOD servers 105, and (v) customer premisesequipment (CPE) 106. The distribution server(s) 104, VOD servers 105 andCPE(s) 106 are connected via a bearer (e.g., HFC) network 101. A simplearchitecture comprising one of each of the aforementioned components102, 104, 105, 106 is shown in FIG. 1 for simplicity.

FIG. 1a illustrates one typical prior art headend architecture. Theheadend architecture 150 comprises typical headend components andservices including billing module 152, subscriber management system(SMS) and CPE configuration management module 154, cable-modemtermination system (CMTS) and OOB system 156, as well as LAN(s) 158, 160placing the various components in data communication with one another.

The architecture 150 of FIG. 1a further includes amultiplexer/encrypter/modulator (MEM) 162 coupled to the HFC network 101adapted to “condition” content for transmission over the network. Thedistribution servers 104 are coupled to the LAN 160, which providesaccess to the MEM 162 and network 101 via one or more file servers 170.The VOD servers 105 are coupled to the LAN 160 as well, although otherarchitectures may be employed (such as for example where the VOD serversare associated with a core switching device such as a Gigabit Ethernetdevice). As previously described, information is carried across multiplechannels. Thus, the headend must be adapted to acquire the informationfor the carried channels from various sources. Typically, the channelsbeing delivered from the headend 150 to the CPE 106 (“downstream”) aremultiplexed together in the headend and sent to neighborhood hubs via avariety of interposed network components.

As shown in FIG. 1b , the network 101 of FIGS. 1 and 1 a comprises afiber/coax arrangement wherein the output of the MEM 162 of FIG. 1a istransferred to the optical domain (such as via an optical transceiver177 at the headend or further downstream). The optical domain signalsare then distributed to a fiber node 178, which further distributes thesignals over a distribution network 180 to a plurality of localservicing nodes 182. This provides an effective 1:N expansion of thenetwork at the local service end. Each local service node 182 providesappropriate content to a “service group” of CPEs 106.

Content (e.g., audio, video, data, files, etc.) is provided in eachdownstream (in-band) channel associated with the relevant service group.To communicate with the headend or intermediary node (e.g., hub server),the CPE 106 may use the out-of-band (OOB) or DOCSIS channels andassociated protocols. The OCAP 1.0, 2.0, 3.0 (and subsequent)specification provides for exemplary networking protocols bothdownstream and upstream.

FIG. 1c illustrates an exemplary prior art “switched” networkarchitecture (e.g., “switched digital video”). Switching architecturesallow improved efficiency of bandwidth use for ordinary digitalbroadcast programs. Ideally, the subscriber is unaware of any differencebetween programs delivered using a switched network and ordinarystreaming broadcast delivery. FIG. 1c shows the implementation detailsof one exemplary implementation of this broadcast switched networkarchitecture. Specifically, the headend 150 contains switched broadcastcontrol and media path functions 190, 192; these element cooperating tocontrol and feed, respectively, downstream or edge switching devices 194at the hub site which are used to selectively switch broadcast streamsto various service groups. A BSA server 196 is also disposed at the hubsite, and implements functions related to switching and bandwidthconservation (in conjunction with a management entity 198 disposed atthe headend). An optical transport ring 197 is utilized to distributethe dense wave-division multiplexed (DWDM) optical signals to each hub.

In addition to “broadcast” content (e.g., video programming), thesystems of FIGS. 1a and 1c also deliver Internet data services using theInternet protocol (IP).

Referring again to FIG. 1c , the IP packets associated with Internetservices are received by edge switch 194, and forwarded to the cablemodem termination system (CMTS) 199. The CMTS examines the packets, andforwards packets intended for the local network to the edge switch 194.Other packets are discarded or routed to another component.

The edge switch 194 forwards the packets received from the CMTS 199 tothe QAM modulator 189, which transmits the packets on one or morephysical (QAM-modulated RF) channels to the CPE. The IP packets aretypically transmitted on RF channels that are different that the RFchannels used for the broadcast video and audio programming (e.g.,DOCSIS QAMs). The CPE 106 are each configured to monitor the particularassigned RF channel (such as via a port or socket ID/address, or othersuch mechanism) for IP packets intended for the subscriberpremises/address that they serve.

Currently, typical “digital” cable networks such as those described withrespect to FIGS. 1-1 c above employ video signals in the TDM domain thatare transformed to FDM (Frequency Division Multiplexing) domain fordelivery within the HFC plant. However, this approach is implemented ina largely discrete fashion; the fundamental technologies perform singlechannel conversion or block up-conversion of multiple adjacent channelsin varying blocks of channels (e.g., 2, 4, 8, 16, or 32). The mostadvanced technologies employed to date perform comb-channel insertion,wherein single channels or blocks of channels are inserted anywherewithin the RF spectrum. This insertion or signal combining iseffectively performed in an analog “wired” domain, which unfortunatelydoes not lend itself to ready reconfiguration without physical rewiring.

For example, in terms of hardware, a typical prior art cable networkhubsite (see FIG. 1c ) has significant requirements in terms of space,power, and cooling due to the many components needed to (i) effect theaforementioned signal combining/insertion functions; and (ii) distributethe combined signal to individual service groups and subscribers. Atypical prior art hubsite rack has 42 Rack Units (RU), and consumesroughly 1 Amp of electrical current per RU (2 Amps if there isredundancy). A hubsite supporting 80 service groups may consume 20 fullracks to generate the necessary spectrums. Moreover, there typically areliterally thousands of wires, specifically coaxial cables, within atypical hubsite. Such complexities are also prone to equipment failure(more components and cables generally equates to a higher chance offailure), and service wiring mistakes.

Hybrid Fiber Copper (HFCu) systems such as the U-Verse® service offeredby AT&T suffer many similar disabilities, largely due to the fact thatthe indigenous transport for much of the provided service (i.e., copperwiring within a user's premises and beyond, that was originallyinstalled for providing POTS or PSTN telephony service only) is notoptimized for narrowcast content delivery.

Another issue with extant content delivery systems relates to so-called“service velocity”; defined as the rate with which new services can beemployed or adopted within a cable or other network. Simply stated, themore difficult such implementation is (due to e.g., having to rewire orreconfigure portions of a network), the lower the velocity. Servicevelocity is an essential differentiating factor in terms of thesubscriber; as time goes on, subscribers want more and better servicesfaster, especially those that are individualized to their particularneeds or situation. Hence, such subscriber-specific service velocitymust be considered in solutions going forward, and extant deliverysystems such as HFC cable topologies cannot be considered optimized forthis factor. Currently, to implement new services, changes to thenetwork topology and significant amounts of labor (e.g., “truck rolls”)are required, due largely to a lack of remote reconfigurationcapability, and what amounts to a largely “circuit switched” topology.

Similarly, to establish or discontinue services for new or existingsubscribers, being so labor-intensive, results in MSOs being reluctantto make these changes without a significant opportunity for economicrecovery (e.g., a commitment from the subscriber for a sufficiently longperiod of time, or a higher rate). Stated differently, if the existingdelivery network could be reconfigured with little or no labor, then thethreshold for establishing/terminating service to a given subscribercould feasibly be lowered (practically corresponding to lower servicecosts, and/or shorter service commitments), which would ostensiblyentice more subscribers to sign up for service, since the cost(risk)-benefit equation tilts further in their favor. This would allownetwork operators such as MSOs to more effectively leverage some oftheir salient advantages or attributes; i.e., customer service,individualization of service, reliability, etc.; as more people try theMSO's service (due to reduced entry threshold), the more people willconceivably be convinced to continue service with the MSO, therebyincreasing the MSO's subscriber base. Conversely, as the subscriber'sservice cost and length of commitment increase, they will be less likelyto sign up or stay with the MSO.

Moreover, current content distribution network infrastructures arepoorly suited for prototyping new technologies. Current prototyping isexpensive for the network (e.g., significant labor and capital outlayswhich may or may not be profitable), and can disrupt consumer services(e.g., as equipment is wired, “juggled”). Faster prototypingcapabilities will benefit both network operators and users/consumers.

Accordingly, there is a salient need for improved apparatus and methodsfor efficiently distributing content (including the aforementionednarrowcast services) within a digital network. Such improved apparatusand services should simplify infrastructures for existing digitalservices, and support other requisite services such as analog, whilealso flexibly accommodating future changes to content deliverymechanisms and services. Rapid and remote reconfigurability would alsobe a highly desirable feature, thereby obviating much labor associatedwith rewiring of traditional networks to add new services.

SUMMARY OF THE INVENTION

The present invention satisfies the foregoing needs by providing, interalia, improved apparatus and methods for optimizing the operation of acontent delivery network by providing adaptive network routing.

In a first aspect of the invention, a network architecture fordistributing content from a plurality of content sources to a pluralityof users is disclosed. In one embodiment, the architecture comprises:spectrum generation apparatus configured to transform signals from afirst domain to a second domain; first apparatus for distributingcontent signals from one or more of the sources to the spectrumgeneration apparatus; and second apparatus for distributing thetransformed content signals to one or more network service groups.

In one variant, the spectrum generation apparatus comprises: a networkinterface adapted to receive digital content from a plurality of contentsources, via the first apparatus; a downstream interface incommunication with the plurality of users via the second apparatus; andprogrammable apparatus configured to transform digital content receivedfrom the network interface from the frequency domain to the time domain.The second apparatus comprises QAM modulated channels.

In another variant, the programmable apparatus configured to transformthe digital content received from the network interface comprises aninverse Fast Fourier Transform (IFFT) apparatus.

In yet another variant, the first apparatus comprises a gigabit Ethernetnetwork, and the second apparatus comprises a substantially circuitswitched frequency distribution network.

In still another variant, the spectrum generation apparatus outputs thetransformed content signals in an optical domain; and the networkarchitecture further comprises an optical-to-radio frequency (RF)coupler adapted to convert the optical domain output of the spectrumgeneration apparatus to an RF domain.

Alternatively, the spectrum generation apparatus outputs the transformedcontent signals in a radio frequency (RF) domain; and the networkarchitecture further comprises an RF combiner adapted to combine the RFdomain output of the spectrum generation apparatus with that of otherspectrum generation apparatus in the same network architecture.

In a second aspect of the invention, a method of providing on-demandcontent to a user of a content distribution network is disclosed. In oneembodiment, the method comprises: receiving a request from a user for adigital content element; accessing the digital content element at anon-demand server; transmitting the accessed digital content element aspart of a single program transport stream (SPTS) to a transformationdevice; transforming, at the transformation device, the received digitalcontent element to one or more time domain signals using digital domainprocessing; and transmitting the transformed signals to the user overone or more radio frequency carriers.

In one variant, the digital content element carried in the SPTS isunencrypted, and the method further comprises encrypting the digitalcontent element before the act of transforming is performed.

In another variant, the method further comprises converting thetransformed digital content element to the analog domain before thetransmitting to the user.

In yet another variant, transmitting the digital content element as partof the SPTS comprises transmitting over a high-capacity packetizedbackbone to the transformation device, the transformation device beingdisposed at a hub site of the network.

In a third aspect of the invention, a method of providing a plurality ofcontent elements to a plurality of users of a content distributionnetwork is disclosed. In one embodiment, the method comprises: accessingat least one of a plurality of digital content sources in communicationwith the network; transmitting the accessed digital content elements aspart of a multi-program transport stream (MPTS) to a transformationdevice; transforming, at the transformation device, the received digitalcontent elements to one or more frequency domain signals using digitaldomain processing; and transmitting the transformed signals to the usersover one or more radio frequency carriers.

In one variant, the transformation device comprises a demultiplexerfunction configured to demultiplex the MPTS to recover individualprogram streams associated with the digital content elements.

In another variant, the one or more frequency carriers compriseQAM-modulated channels each having a frequency bandwidth ofapproximately 6 MHz.

In another variant, the digital domain processing comprises an inverseFast Fourier Transform (IFFT).

In yet another variant, the plurality of users are associated with acommon service group within the network.

In a further variant, the transformation device is substantiallyremotely reprogrammable, and the method further comprises dynamicallychanging an allocation of the transformed digital content elements tothe one or more frequency carriers remotely.

In still another variant, the transformation device is substantiallyremotely reprogrammable, and the method further comprises dynamicallychanging an allocation of the transformed digital content elements tothe one or more frequency carriers remotely.

In another variant, the method further comprises dynamically insertingsecondary content elements into the digital content elements before thetransformation.

In a fourth aspect of the invention, a method of providing a pluralityof heterogeneous types of content products to various ones of aplurality of users of a content distribution network is disclosed. Inone embodiment, the method comprises: receiving the heterogeneous typesof content from one or more content sources; allocating the differenttypes of content to frequency resources; performing digital domainprocessing on the content to effect the allocating; and transmitting theconverted content to the plurality of users over the allocated frequencyresources. The transmitting of the converted content comprisestransmitting without forming a multi-program transport stream.

In a fifth aspect of the invention, a content distribution network isdisclosed. In one embodiment, the network has a substantially flattopology and comprises: spectrum generation apparatus disposedsubstantially at an edge of the network and configured to performdigital domain processing of content to transform the content from amultiplexed frequency domain input to a time domain output; firstapparatus for distributing the content from one or more sources to thespectrum generation apparatus; and second apparatus for distributing thetransformed content to one or more network service groups. Thetransformed content is delivered to the one or more service groupswithout having to be multiplexed into a transport stream.

In another embodiment, the network comprises: spectrum generationapparatus disposed substantially at an edge of the network andconfigured to perform digital domain processing of content to transformthe content from a frequency domain input to a time domain output; firstapparatus for distributing the content from one or more sources to thespectrum generation apparatus; and second apparatus for distributing thetransformed content a plurality of hierarchical service groups that arevirtually created in a time division multiplexed domain, and subscribedto by the spectrum generation apparatus. The spectrum generationapparatus further is configured to perform combining of a plurality ofsignals in the digital domain without the need for RF combining andinsertion using physical conduction media.

In a sixth aspect of the invention, methods of doing business utilizingthe previously referenced network and architecture are disclosed.

In an seventh aspect of the invention, methods of providing high servicevelocity utilizing previously referenced network and architecture aredisclosed.

In an eighth aspect of the invention, a network distributionarchitecture utilizing multiple ones of the spectrum generation deviceis disclosed.

In another aspect, a method of providing on-demand content to a user ofa content distribution network is disclosed. In one embodiment, themethod includes: receiving a request from a user for a digital contentelement; accessing the digital content element at an on-demand server;transmitting the accessed digital content element as part of a singleprogram transport stream (SPTS) to a transformation device;transforming, at the transformation device, the received digital contentelement to one or more time domain signals using digital domainprocessing; and transmitting the transformed signals to the user overone or more radio frequency carriers.

In one variant, the digital content element carried in the SPTS isunencrypted, and the method further comprises encrypting the digitalcontent element before the act of transforming is performed.

In another variant, the method further includes converting thetransformed digital content element to the analog domain before thetransmitting to the user.

In a further variant, transmitting the digital content element as partof the SPTS comprises transmitting over a high-capacity packetizedbackbone to the transformation device, the transformation device beingdisposed at a hub site of the network.

In another variant, the digital domain processing comprises an inverseFast Fourier Transform (IFFT).

In still another variant, the transformation device is substantiallyremotely reprogrammable, and the method further comprises dynamicallychanging an allocation of the transformed digital content element to theone or more frequency carriers remotely.

In another variant, the method further includes dynamically insertingone or more secondary content elements into the digital content elementbefore the transformation.

In yet a further variant, the SPTS comprises a unicast SPTS, and themethod further includes: providing the digital content element to ascheduler apparatus via a multicast SPTS, the scheduler apparatusconfigured to segment a plurality of program streams into a plurality offiles; selecting one or more of the plurality of files corresponding tothe digital content element to be utilized by the on-demand server; andcausing storage of the selected one or more files on a storage apparatusassociated with the on-demand server, the stored one or more filessubsequently being used to form at least a portion of the unicast SPTS.

In one implementation, the scheduler apparatus is configured to applymetadata content to the selected one or more files prior to the storage,and/or the selected one or more files corresponding to the digitalcontent element carried in the unicast SPTS is/are unencrypted, and themethod further comprises encrypting the selected one or more filesbefore the act of transforming is performed.

In another aspect, a method of providing on-demand content to a user ofa content distribution network is disclosed. In one embodiment, theon-demand content has a broadcast-related start time associatedtherewith, and the method includes: receiving a broadcast containing thedigital content element as part thereof; processing at least a portionof the broadcast to obtain the digital content element for storage on astorage device associated with an on-demand server; receiving a requestfrom a user for a digital content element, the request originated afterthe start time and causing creation of a session for that user;accessing the digital content element at the storage device;transmitting the accessed digital content element as part of a unicastsingle program transport stream (SPTS) to a transformation device;transforming, at the transformation device, the received digital contentelement to one or more time domain signals using digital domainprocessing; and transmitting the transformed signals to the user overone or more radio frequency carriers, the transmitting commencing afterthe start time and the receiving a request.

In yet another aspect, a network apparatus configured to deliver contentfrom an on-demand digital content source to at least one user associatedwith a content distribution network is disclosed. In one embodiment, thenetwork apparatus includes: a first interface configured to access theon-demand digital content source, the on-demand digital content sourcein communication with the content distribution network; a storageapparatus in data communication with the first interface and configuredto at least temporarily store at least an accessed digital contentelement obtained from the digital content source; a remotelyreprogrammable transformation device, and a second interface configuredto transmit transformed one or more time domain signals to the at leastone user over at least one radio frequency carrier.

In one variant, the remotely programmable device is configured to:receive the accessed digital content element as part of a unicastsingle-program transport stream (SPTS); transform the digital contentelement into one or more one or more time domain signals via digitaldomain processing.

In another variant, the at least one radio frequency carrier comprisesat least one QAM-modulated channel, and the digital domain processingcomprises an inverse Fast Fourier Transform (IFFT).

In a further variant, the first interface comprises an interface to agigabit Ethernet network, and the second interface comprises aninterface to substantially circuit switched frequency distributionnetwork.

In another variant, the transformation device is disposed at a hubsiteof a content distribution network and away from a core of the contentdistribution network.

In yet another aspect, a network apparatus configured to deliver contentfrom a digital content source to at least one user associated with acontent distribution network is disclosed. In one embodiment, thedelivery is accomplished via at least switched digital delivery, and thenetwork apparatus includes: a first interface configured to access thedigital content source to obtain a variable bitrate (VBR) digitalcontent element, the digital content source in communication with thecontent distribution network; computerized logic apparatus in datacommunication with the first interface and configured to clamp theaccessed VBR digital content element so as to produce a correspondingconstant bitrate (CBR) digital content element; second computerizedlogic apparatus in data communication with the first computerized logicand configured to encrypt at least a portion of the CBR digital contentelement to produce an encrypted CBR digital content element; a remotelyreprogrammable transformation device in data communication with at leastthe second logic and configured to: receive the encrypted CBR digitalcontent element as part of a multicast single-program transport stream(SPTS) being distributed to the remotely programmable transformationdevice and a plurality of other corresponding remotely reprogrammabletransformation devices within the network; transform the encrypted CBRdigital content element from a first domain to a second, differentdomain via digital domain processing; and a second interface configuredto transmit the transformed one or more second domain content to aplurality of users over at least one radio frequency carrier and via aswitched delivery apparatus, the switched delivery apparatus comprisinglogic configured to selectively switch in and switch out the encryptedCBR digital content element from delivery based at least on a presenceor absence of a user being tuned to the at least one radio frequencycarrier.

Other features and advantages of the present invention will immediatelybe recognized by persons of ordinary skill in the art with reference tothe attached drawings and detailed description of exemplary embodimentsas given below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a functional block diagram illustrating an exemplary prior artHFC cable network configuration.

FIG. 1a is a functional block diagram illustrating one exemplary priorart HFC cable network headend configuration.

FIG. 1b is a functional block diagram illustrating one exemplary priorart local service node configuration.

FIG. 1c is a functional block diagram illustrating one exemplary priorart broadcast switched architecture (BSA) network.

FIG. 2a is a graphical representation of the various domains within anexemplary network employing the edge device of the present invention.

FIG. 2b is a functional block diagram illustrating a first networkarchitecture useful with the edge device of the present invention,wherein the edge devices are disposed at one or more hubsites.

FIG. 2c is a functional block diagram illustrating another exemplarynetwork configuration useful with the edge device of the presentinvention, this configuration being substantially optimized forpacketized (e.g., IP-encapsulated) content distribution and delivery.

FIG. 2d is a functional block diagram illustrating another embodiment ofa network architecture according to the present invention.

FIG. 2e is a functional block diagram illustrating yet anotherembodiment of a network architecture according to the present invention.

FIG. 2f is a functional block diagram illustrating yet a furtherembodiment of a network architecture according to the present invention.

FIG. 2g is a logical block diagram illustrating the signal flow foranalog broadcast content delivery within one exemplary architecture ofthe network.

FIG. 2h is a logical block diagram illustrating the signal flow for VODcontent delivery within one exemplary architecture of the network.

FIG. 2i is a logical block diagram illustrating the signal flow for VODwith “start-over” functionality within one exemplary architecture of thenetwork.

FIG. 2j is a logical block diagram illustrating the signal flow forswitched (e.g., SDV multicast) content delivery within one exemplaryarchitecture of the network.

FIG. 3 is a prior art spectrum allocation illustrating the variousdeficiencies of prior art cable network content distribution.

FIG. 4 is a graphical illustration of several spectrum allocationconfigurations enabled by one exemplary embodiment of the presentinvention.

FIG. 5 is a graphical representation of one exemplary embodiment of aspectrum generation device, in accordance with the present invention.

FIG. 6 is a graphical representation of a Look Up Table (LUT) useful inimplementing various embodiments of the present invention.

FIG. 7 is a graphical illustration of the mathematical relationshipbetween the Fast Fourier Transform and the Inverse Fast FourierTransform.

FIG. 8a is a functional block diagram illustrating the internaloperations of one exemplary embodiment of the spectrum generationdevice, in accordance with the present invention.

FIG. 8b is a functional block diagram illustrating the internaloperations of a second exemplary embodiment of the spectrum generationdevice, in accordance with the present invention.

FIG. 9 is a logical flow diagram illustrating a generalized method fordistributing content, in accordance with the present invention.

FIG. 9a is a logical flow diagram illustrating one specificimplementations of the method for distributing content of FIG. 9.

FIG. 10 is a graphical representation of analog reclamation, asaccomplished by one exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Reference is now made to the drawings wherein like numerals refer tolike parts throughout.

As used herein, the term “application” refers generally to a unit ofexecutable software that implements a certain functionality or theme.The themes of applications vary broadly across any number of disciplinesand functions (such as on-demand content management, e-commercetransactions, brokerage transactions, home entertainment, calculatoretc.), and one application may have more than one theme. The unit ofexecutable software generally runs in a predetermined environment; forexample, the unit could comprise a downloadable Java Xlet™ that runswithin the JavaTV™ environment.

As used herein, the term “computer program” or “software” is meant toinclude any sequence or human or machine cognizable steps which performa function. Such program may be rendered in virtually any programminglanguage or environment including, for example, C/C++, Fortran, COBOL,PASCAL, assembly language, markup languages (e.g., HTML, SGML, XML,VoXML), and the like, as well as object-oriented environments such asthe Common Object Request Broker Architecture (CORBA), Java™ (includingJ2ME, Java Beans, etc.), Binary Runtime Environment (e.g., BREW), andthe like.

The terms “Customer Premises Equipment (CPE)” refer to any type ofelectronic equipment located within a customer's or user's premises andconnected to a network, including devices having access to digitaltelevision content via a satellite, cable, or terrestrial network. Theterm “customer premises equipment” (CPE) includes such electronicequipment such as (and without limitation) set-top boxes (e.g., DSTBs),televisions, cable modems (CMs), embedded multimedia terminal adapters(eMTAs), whether stand-alone or integrated with other devices, DigitalVideo Recorders (DVR), gateway storage devices (e.g., Furnace), and ITVPersonal Computers.

As used herein, the term “display” means any type of device adapted todisplay information, including without limitation: CRTs, LCDs, TFTs,plasma displays, LEDs, incandescent and fluorescent devices. Displaydevices may also include less dynamic devices such as, for example,printers, e-ink devices, and the like.

As used herein, the term “DOCSIS” refers to any of the existing orplanned variants of the Data Over Cable Services InterfaceSpecification, including for example DOCSIS versions 1.0, 1.1, 2.0 and3.0. DOCSIS (version 1.0) is a standard and protocol for internet accessusing a “digital” cable network.

As used herein, the term “DVR” (digital video recorder) refers generallyto any type of recording mechanism and/or software environment, locatedin the headend, the user premises or anywhere else, whereby content sentover a network can be recorded and selectively recalled. Such DVR may bededicated in nature, or part of a non-dedicated or multi-functionsystem.

As used herein, the term “headend” refers generally to a networkedsystem controlled by an operator (e.g., an MSO or multiple systemsoperator) that distributes programming to MSO clientele using clientdevices. Such programming may include literally any informationsource/receiver including, inter alia, free-to-air TV channels, pay TVchannels, interactive TV, and the Internet.

As used herein, the terms “Internet” and “internet” are usedinterchangeably to refer to inter-networks including, withoutlimitation, the Internet.

As used herein, the term “memory” includes any type of integratedcircuit or other storage device adapted for storing digital dataincluding, without limitation, ROM. PROM, EEPROM, DRAM, SDRAM, DDR/2SDRAM, EDO/FPMS, RLDRAM, SRAM, “flash” memory (e.g., NAND/NOR), andPSRAM.

As used herein, the terms “processor”, “microprocessor” and “digitalprocessor” are meant generally to include all types of digitalprocessing devices including, without limitation, digital signalprocessors (DSPs), reduced instruction set computers (RISC),general-purpose (CISC) processors, microprocessors, gate arrays (e.g.,FPGAs), PLDs, reconfigurable compute fabrics (RCFs), array processors,secure microprocessors, and application-specific integrated circuits(ASICs). Such digital processors may be contained on a single unitary ICdie, or distributed across multiple components.

As used herein, the terms “MSO” or “multiple systems operator” refer toa cable, fiber to the home (FTTH), fiber to the curb (FTTC), satellite,HFCu, or other terrestrial network provider having infrastructurerequired to deliver services including programming and data over thosemediums.

As used herein, the terms “network” and “bearer network” refer generallyto any type of telecommunications or data network including, withoutlimitation, hybrid fiber coax (HFC) networks, satellite networks,wireless networks, telco networks, and data networks (including MANs,WANs, LANs, WLANs, internets, and intranets). Such networks or portionsthereof may utilize any one or more different topologies (e.g., ring,bus, star, loop, etc.), transmission media (e.g., wired/RF cable, RFwireless, millimeter wave, optical, etc.) and/or communications ornetworking protocols (e.g., SONET, DOCSIS, IEEE Std. 802.3, ATM, X.25,Frame Relay, 3GPP, 3GPP2, WAP, SIP, UDP, FTP, RTP/RTCP, H.323, etc.).

As used herein, the term “network interface” refers to any signal, data,or software interface with a component, network or process including,without limitation, those of the FireWire (e.g., FW400, FW800, etc.),USB (e.g., USB2), Ethernet (e.g., 10/100, 10/100/1000 (GigabitEthernet), 10-Gig-E, etc.), MoCA, Serial ATA (e.g., SATA, e-SATA,SATAII), Ultra-ATA/DMA, Coaxsys (e.g., TVnet™), radio frequency tuner(e.g., in-band or OOB, cable modem, etc.), Wi-Fi (802.11a,b,g,n), WiMAX(802.16), PAN (802.15), or IrDA families.

As used herein, the term “QAM” refers to modulation schemes used forsending signals over cable networks. Such modulation scheme might useany constellation level (e.g. QPSK, QAM-16, QAM-64, QAM-256 etc.)depending on details of a cable network. A QAM may also refer to aphysical channel modulated according to the schemes.

As used herein, the term “server” refers to any computerized component,system or entity regardless of form which is adapted to provide data,files, applications, content, or other services to one or more otherdevices or entities on a computer network.

As used herein, the term “service”, “content”, “program” and “stream”are sometimes used synonymously to refer to a sequence of packetizeddata that is provided in what a subscriber may perceive as a service. A“service” (or “content”, or “stream”) in the former, specialized sensemay correspond to different types of services in the latter,non-technical sense. For example, a “service” in the specialized sensemay correspond to, among others, video broadcast, audio-only broadcast,pay-per-view, or video-on-demand. The perceivable content provided onsuch a “service” may be live, pre-recorded, delimited in time,undelimited in time, or of other descriptions. In some cases, a“service” in the specialized sense may correspond to what a subscriberwould perceive as a “channel” in traditional broadcast television.

As used herein, the term “storage device” refers to without limitationcomputer hard drives, DVR device, memory, RAID devices or arrays,optical media (e.g., CD-ROMs, Laserdiscs, Blu-Ray, etc.), or any otherdevices or media capable of storing content or other information.

As used herein, the term “user interface” refers to, without limitation,any visual, graphical, tactile, audible, sensory, or other means ofproviding information to and/or receiving information from a user orother entity.

As used herein, the term “Wi-Fi” refers to, without limitation, any ofthe variants of IEEE-Std. 802.11 or related standards including802.11a/b/g/n/v.

As used herein, the term “wireless” means any wireless signal, data,communication, or other interface including without limitation Wi-Fi,Bluetooth, 3G, HSDPA/HSUPA, TDMA, CDMA (e.g., IS-95A, WCDMA, etc.),FHSS, DSSS, GSM, PAN/802.15, WiMAX (802.16), 802.20, narrowband/FDMA,OFDM, PCS/DCS, analog cellular, CDPD, satellite systems, millimeter waveor microwave systems, acoustic, and infrared (i.e., IrDA).

Overview

The present invention discloses, inter alia, methods and apparatus fordistributing content from a plurality of content sources, via a spectrumgeneration device to a plurality of subscribers. In one exemplaryembodiment, the methods and apparatus of the present invention provide atechnique for receiving digital content via a time-multiplexed network(such as Gigabit Ethernet), and converting the digital content to QAMssuitable for transmission over e.g., a Hybrid Fiber Coaxial (HFC)network. As described in greater detail herein, the conversion isperformed by a substantially unified full spectrum generation device.Various aspects of the present invention advantageously enable physicalconsolidation and software management of content distribution.

In one aspect of the invention, the full spectrum generation device canreplace a wide array of existing cable or terrestrial networkinfrastructure elements. Traditional equipment for splicing, mixing,etc. signals within the analog domain can be replaced by the fullspectrum device, which executes the foregoing functions within thedigital domain. Digital signal processing is much more power efficient,compact, and easy to manage (and remotely control) than its analogcounterparts.

Additionally, digital signal processing enables higher qualityreproduction of the content for the subscriber audience. Noise isintroduced during analog signal processing stages; thus, performingsignal processing within the digital domain maintains higher levels offidelity over analog equivalents. By generating the entire spectrumdirectly from the digital content; the original content is maximallypreserved, since there are no intermediate “analog” operations (e.g.,combining, mixing, splicing, A/D or D/A conversion, etc.).

In one exemplary embodiment, a programmable full spectrum deviceconverts digital content from a time-multiplexed network to afrequency-multiplexed network. The full spectrum generation devicecomprises a time-multiplexed network interface, a frequency-multiplexeddownlink interface, and a programmable device (e.g., substrate) adaptedto convert content from the frequency domain to the time domain.Additionally, as described in greater detail herein, various optionalembodiments may include additional processors or logic to facilitateconfiguration of the programmable device by, inter alia, external orremote network entities.

In the exemplary embodiment, digital content is transformed between thedomains (e.g., frequency to time) using an Inverse Fast FourierTransform (IFFT). This transformation is provided by a substantiallyunified digital-domain processing edge device that generates the entirerequired spectrum (e.g., 54 MHz-1 GHz), and outputs RF or direct lasersignals for delivery to subscribers. In one implementation, a single RFdevice per service group provides all services including analog, digitalbroadcast, VOD, switched digital content delivery, high-speed data,etc.). The RF devices (for each service group) are configured to supportVOD and switched digital protocols, and share bandwidth across thedifferent services. External “bulk encryptors” are utilized for bothbroadcast, common-tier and session-based encryption.

The foregoing exemplary embodiment does not eliminate extanthierarchical service groups; rather, these groups are “virtualized” inthe TDM domain, and subscribed to by the aforementioned unified edgedevice that performs the signal transformation to the FDM domain. Thesignal “combining” historically performed in the FDM domain is in oneembodiment accomplished by the use of advanced Digital Signal Processing(DSP), Field Programmable Gate Array (FPGA), and Digital-to-AnalogConverter (DAC) technologies (instead of RF combining/insertion withphysical wires as previously described).

The use of the aforementioned unified edge device thereforeadvantageously: (i) resolves hubsite environmental constraints of space,power and cooling; (ii) simplifies and reduces narrowcast complexity;(ii) substantially obviates re-wiring for narrowcast services; (iii)provides a redundancy and resiliency for services; and (iv) provides ahighly reconfigurable dynamic platform to support accelerated newservice implementation or modification (higher service velocity).

Additionally, various interoperability aspects of the present inventionsupport co-existence with legacy network infrastructures. Businessmodels incorporating various aspects of the present invention are alsodescribed.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Exemplary embodiments of the apparatus and methods of the presentinvention are now described in detail. While these exemplary embodimentsare described for operation within hybrid fiber coax (HFC) cable or HFCuterrestrial networks, the general principles and advantages of theinvention may be extended to other types of networks and architectures,whether broadband, narrowband, wired or wireless, terrestrial orspace-based, or otherwise, the following therefore being merelyexemplary in nature.

It is further noted that while described primarily in the context of acable delivery system, the present invention is applicable to literallyany network topology or paradigm. Furthermore, while example frequencybandwidths and timing schedules are described throughout, the inventionis in no way limited to the specified frequencies, timing, etc. Suchphysical aspects of data transmission are subject to applicablestandards, and may change in future incarnations, yet in no way areessential to practicing the invention.

Also, while certain aspects are described primarily in the context ofthe well-known IP or Internet Protocol (described in, inter alia, RFC791 and 2460), it will be appreciated that the present invention mayutilize other types of protocols (and in fact bearer networks to includeother internets and intranets) to implement the described functionality.

Moreover, while the exemplary full spectrum device is also hereinreferred to as an “edge” device, it is appreciated that the device isnot limited to network edge applications. For instance, in oneimplementation, multiple full spectrum devices are placed at nodesupstream from the hubsites, so that their outputs can be routed to oneor more downstream hubs simultaneously. Alternatively, smaller fullspectrum generation devices can be implemented downstream, closer to (orwithin) the consumer premises. For example, spectrum generation at theconsumer premises could support, inter alia, advanced networkinfrastructure (e.g., Ethernet over fiber, etc.) for legacy devices; thespectrum device generates legacy spectrum formats for legacy CPEs.

Other features and advantages of the present invention will immediatelybe recognized by persons of ordinary skill in the art with reference tothe attached drawings and detailed description of exemplary embodimentsas given below.

Design Features—

As previously stated, prior art cable networks rely on a plethora ofanalog stages for single channel conversion, block up-conversion, combchannel insertion, etc. to insert narrowcast services piecemeal into theexisting cable spectrum. In contrast, one exemplary implementation ofthe present invention converts Time Division Multiplexing (TDM) datastreams from multiple source devices to Frequency Division Multiplexing(FDM) data streams consumed at multiple sink devices (e.g., CPEs). Theunified edge device receives a number of input data streams via e.g., aGig-E (Gigabit Ethernet) backbone, and transmits the entire cablespectrum (e.g., 54 MHz-1 GHz). The cable spectrum may be provided in RF,or direct laser output (for optical coupling). A single edge device cangenerate the entire frequency spectrum for supporting multiplesubscriber “narrowcast” services e.g., Digitized Analog, Digital,Video-On-Demand (VOD), Switched Digital Video (SDV), High Speed Data(HSD), etc. The desired services (for the group of subscribers) arereceived at the edge device, converted to the frequency domain, andcombined to form the entire spectrum transmitted to the servedsubscribers. Different modulation types (e.g., QAM, QPSK, etc.) aresupported for the different services as needed.

Physical Consolidation—

As will be readily appreciated the exemplary edge device substantiallyreduces (or eliminates) combining, cascading, splitting, mixing, etc. ofthe type performed under prior art implementations. Hardware forcascading, combining, filtering, etc. can consume tremendous amounts ofRF energy, as well as space, electrical power, and other resources.Elimination of these intermediate stages greatly improves powerconsumption, while also reducing the physical/hardware “footprint”needed to provide equivalent service. Also, consolidation of spectrumgeneration within a single entity greatly reduces the wiring or cablingnecessary. Less wiring corresponds to further reductions in powerconsumption, and minimizes human error (e.g., mis-wiring, faulty wiring,etc.). Power considerations directly impact space, cooling requirementsand other physical restrictions. For example, one exemplary embodimentof the edge device described herein consumes on the order of 0.5 (pointfive) Amps, and occupies roughly one-half of a hubsite server Rack Unit(RU). Hence, very significant space and power savings are realized ascompared to the prior art previously discussed herein (i.e., up to 2(two) Amps and 20 (twenty) full racks).

Moreover, fewer components and cables generally translate to lessopportunity for component failure, and hence enhanced reliability.

Furthermore, the reduction of intermediate stages greatly improvessignal quality. The spectrum generated by the edge device hassignificantly higher fidelity than equivalent prior art structures.Prior art solutions for removing or adding narrowcast content requiredmultiple intermediate stages for removing existing QAMs, adding newQAMs, etc.; each intermediate stage cumulatively adds additional noise.In contrast, the edge device described herein generates the entirespectrum directly from the digital content; the signal integrity iscompletely preserved, since there are no intermediate “analog”operations (e.g., combining, mixing, splicing, etc.).

Software-based Support—

In addition to the various physical advantages of edge device augmentednetworks, in one embodiment of the present invention, each edge devicecomprises a reconfigurable fabric for software programmable operation.Such reconfigurable fabric may be implemented for example using one ormore Field Programmable Gate Arrays (FPGAs) or other Programmable LogicDevices (PLDs), or Reconfigurable Compute Fabrics (RCFs). Othervariations may be virtualized within a multitude of dedicatedprocessors, such as DSPs (Digital Signal Processors) or processor cores,Fast DACs (Digital to Analog Converters etc.

Consider traditional network “edges”; modifications to hub sites mightrange from changing service offerings to subscribers, to featureupgrades. In either case, technicians must be deployed physically to thehub site or other location to rewire the affected rack units. Further,in some cases, new hardware and software must be installed.Unfortunately, manual configuration is a time consuming, expensive anderror prone process.

The edge device software configurability of the edge device of theinvention has very significant implications for network maintenance andupkeep costs. Perhaps most notably, the edge device can be reconfiguredentirely in software. For example, changing a standard definition (SD)channel to a high definition (HD) channel could be performed with afirmware update. Similarly, adding a new content source (e.g., VOD, SDV,etc.) might entail changing or adding an entry for the content source'snetwork address.

In addition to being virtually instant and resistant to human error,reconfiguration can advantageously be performed remotely. Streamlinedupdating may be performed for the entire cable network, from anyauthorized network terminal (e.g., one disposed at the headend). Networkmanagement provides other flexible upgrade possibilities not previouslypossible; for example, one edge device could incorporate content frommultiple devices maintained in remote facilities, where the content isspecified entirely by network address. Such networked content may beleveraged to flexibly support unexpected “overflow” conditions, variousdemographics or geographics, or even trial installations.

Additionally, in certain embodiments, reconfiguration can be madeentirely automated. Unlike manual procedures which require human upkeepand execution, automated reconfiguration may be useful to respond tocertain “trigger” conditions, or efficiently shift resource allocationsto satisfy real-time subscriber preferences. For example, unexpectedpeaks of demand for content can trigger automatic reconfiguration ofresource allocations or service groups, without requiring technicianintervention. This approach also helps provide enhanced networkrobustness to varying and unpredictable operating conditions, in thatthe network is dynamically adaptive and substantially “self healing”.

Edge Device-Based Network Architectures—

The edge device augmented network can receive a number of input datastreams via e.g., a Gig-E (Gigabit Ethernet) backbone from multiplecontent sources within a content delivery network, and generate theentire frequency spectrum for a population of CPE. The exemplary edgedevice network is thus substantially “flattened” in comparison totypical hierarchical networks which use multiple stages of analogcomponents to insert, mix, or remove channels in the analog domain. Aspreviously described, since the entire spectrum is generated directlyfrom the digital content, the introduction of noise from analog elementsis reduced and/or nullified. The inventive network is truly “alldigital” in terms of content processing.

FIG. 2a illustrates an exemplary content processing and distributionscheme 200 for one exemplary service group comprising a number of CPE inaccordance with the present invention. As shown in FIG. 2a , a fullspectrum edge device 204 receives time-multiplexed content 206 from anumber of content sources 208, and generates the comprehensive spectrum210 for a plurality of tuners 202 served by the service group. While thefollowing discussions are described within a TDM-to-FDM based system,the multiplexing method is a design selection for one exemplary networkimplementation, and is not a required to practice the present invention.For example, in alternate embodiments, the full spectrum edge device mayreceive FDM streams and produce TDM outputs. Similarly, the fullspectrum edge device may receive FDM streams and regenerate new FDMstreams, or juggle scheduling for a number of TDM inputs to TDM outputs.

Moreover, it is appreciated that other multiplexing schemes may be usedgiven the contents of the present disclosure. For example, current cablenetworks incorporate fiber optic cabling which use coarse wave divisionmultiplexing (CWDM) schemes. CWDM is one variant of a family ofwave-division multiplexing (WDM) technologies which multiplexes multiplesignals using different wavelengths of light for each signal. Other WDMtechnologies include dense wave division multiplexing (DWDM), UltraDWDM, etc. Thus, certain fiber optic embodiments of the presentinvention are adapted to convert multiple TDM streams to CWDM streamsfor transmission over fiber optic cabling.

FIG. 2b illustrates one exemplary embodiment of a “flattened” networkarchitecture employing the edge device 204. As shown, the networkarchitecture 250 is generally comprised of a headend 252, a contenttransport portion 254, a plurality of hubsites or other distributionnodes 256, and a plurality of served CPE 106. In variousimplementations, the transport portion may comprise any number ofdifferent components and transport modalities. For instance, in oneembodiment, the transport 254 comprises a Gigabit Ethernet (Gig-E)backbone of the types well known in the networking arts.

The Gig-E backbone is already resident in many extant cable and othernetwork architectures, and hence can be used for packet-switcheddelivery of content to the various hubsites. For instance, the Gig-Ebackbone can carry one or more multiplexed content streams (somewhatakin to an MPTS, yet over the Gig-E packet switched domain and withoutan underlying MPEG container). These common streams can be broadcast(e.g., to all hubsites), or multicast (i.e., only to specific hubsites),or even unicast to one destination as desired, and accordingly may beheterogeneous or homogenous in terms of content carried.

In another embodiment, the transport portion may comprise one or moreoptical networks (e.g., CWDM, DWDM, Ultra DWDM, etc.) and other portionsof the extant cable plant to distribute the multiplexed stream(s) to thevarious hubsites.

In yet another embodiment, a circuit-switched network could be used tocarry the content to the various hubsites; e.g., Asynchronous TransferMode (ATM). As is well known, ATM employs 53-byte packets for payloaddelivery, yet carries these packets via logical pathways and circuitscalled VPIs and VCIs respectively.

As a further alternative, a wireless transport might be used; e.g.,WiMAX (IEEE Std. 802.16) or millimeter wave system, or even satellite.

Disposed at each hubsite 256 are one or more full spectrum edge devices204 of the type previously described. These devices: (i) demultiplex thetime-multiplexed content streams delivered over the transport 254 intoindividual program streams; (ii) assign or allocate each of the programstreams to a frequency resource (note that multiple program streams maybe 25 assigned to the same resource if desired), and (iii) performconversion of the streams to the time domain using e.g., an IFFToperation or other domain transformation. The edge device is configuredwith sufficient processing power (described below) to generate allportions of the requisite frequency spectrum simultaneously, in onevariant using a plurality of parallel IFFT “engines” which can performthe requisite IFFT calculations at high speed to support the 30 domaintransformation of large amounts of data (approximately 6.2 Gbps; i.e.,160 channels multiplied by 38.8 Mbps per channel) of streamed content.

CPE 106 (e.g., digital STBs, etc.) equipped with an RF tuner can tune tothe appropriate portion of the generated spectrum to receive anddemodulate the program stream of interest, akin to a normal STBarrangement. For example, current cable networks dedicate an additionalchannel for carrying system information (e.g., current programminginformation, etc.). Exemplary embodiments provide a dedicated QPSK(Quadrature Phase Shift Keying) modulated channel; this control channelprovides system data via well known protocols e.g., ALOHA accessprotocols (e.g., pure ALOHA, slotted ALOHA, etc.), and DAVIC (DigitalAudio Video Council) protocols, although it will be appreciated thatother approaches may be used consistent with the invention.

In some embodiments, the full spectrum edge device 204 aligns itselfwith received system information. For example, the full spectrum devicemay receive current programming information from a higher networkentity. After programming its internal channel interfaces, the fullspectrum edge device provides the resultant spectrum, and theaccompanying control channels to the service group, consistent with thereceived system information.

In alternate embodiments, the full spectrum edge device 204 generatesthe control channel internally, based on its internal operations. Forexample, the full spectrum device may dynamically assign program streamsto various frequency resources. Thereafter, the full spectrum edgedevice also generates the programming information, such that itsserviced CPEs can track current programming, transparent to thecustomer. In one such example, the full spectrum edge device canflexibly assign content to any number of channels; the CPE is notified(via control channel) of current programming. When the customer selectscontent of interest, the CPE references its internal record (whichmatches content to channels), and accesses the proper channel.

While the foregoing network architectures described herein can (and infact do) carry packetized content (e.g., IP over MPEG for high-speeddata or Internet TV, MPEG2 packet content over QAM for MPTS, etc.), theyare often not optimized for such delivery (i.e., an all-IP model).Hence, in accordance with another embodiment of the present invention, a“packet optimized” delivery network is used for carriage of the packetcontent (e.g., IPTV content). FIG. 2c illustrates one exemplaryimplementation of such a network, in the context of a 3GPP IMS (IPMultimedia Subsystem) network with common control plane and servicedelivery platform (SDP), as described in U.S. provisional patentapplication Ser. No. 61/256,903 filed Oct. 30, 2009 and entitled“METHODS AND APPARATUS FOR PACKETIZED CONTENT DELIVERY OVER A CONTENTDELIVERY NETWORK, incorporated herein by reference in its entirety. Thisarchitecture makes pervasive use of IP-protocol content of all types(i.e., high speed data, IPTV content, etc.), with IP being the commonnetwork protocol so as to permit various types of functions includingconverged services and platforms, mobility, high service velocity, etc.

In the case of the edge device of the present invention, the multiplexedcontent stream received at each hub site may be encapsulated within anIP “wrapper” (as well as its native lower layer protocol; e.g., Gig-E),akin to IP-packetized content being carried over an Ethernet LAN, Wi-Fibearer, etc. In some embodiments of the present invention, themultiplexed content stream is transmitted by the edge device “as is”;i.e., the encapsulated content is transmitted in encapsulated form tothe subscriber CPE, service group, etc. In alternate embodiments, themultiplexed content is extracted and transmitted. In some variants, theextracted content may be re-encapsulated with a new IP wrapper, orotherwise re-coded for transmission.

One exemplary delivery paradigm using the network of FIG. 2c comprisesdelivering MPEG-based video content, with the video transported to userPCs (or IP-based DSTBs) over the allocated portion(s) of the frequencyspectrum comprising MPEG (or other video codec such as H.264/AVC) overIP over a container (e.g., MPEG). That is, the higher layer MPEG-2,H.264 or other encoded content is encapsulated using an IP protocol,which then utilizes an MPEG packetization of the type well known in theart for delivery over the RF channels.

Those of ordinary skill in the related arts will readily appreciate thebenefits of the present invention and the potential future innovationsin content distribution networks enabled therefrom. For example, in theaforementioned all IP network, consider a hubsite that supports DOCSIS3.0 for a prototype consumer audience (e.g., twenty (20) servicegroups). As deployment matures over time, the number of service groupswill increase in size and shrink in number of consumer's serviced,conceivably until each CPE has a personal service group (severalhundred). Using prior art rollout methods, each new service grouprequires rewiring, restacking, etc. In contrast to prior art solutions,one embodiment of the present invention can be dynamically and remotelyreprogrammed to adjust its operation according to this model.

FIG. 2d illustrates a first embodiment of a high-level networkarchitecture according to the invention. As shown, a plurality ofcontent signal sources 262 feed a transport network (e.g., GigE) 254,which supplies input to the SGD stage having a plurality of SGDs 204.The embodiment of FIG. 2d notably utilizes a direct laser (opticaldomain) output from the SGD 204 into the downstream network andnarrowcast service groups 266. A 1-to-1 laser-to-node ratio is utilizedin this embodiment, although other ratios (e.g. 1-to-N) may be utilizedconsistent with the invention. The SGD outputs modulated digitizedanalog, as well as digital broadcast, SDV, VOD, RF two-way, and DOCSIS1.0 and 3.0 signals in the optical domain. These optical domain signalsare then converted to the RF domain via one or more optical-RF couplers264 of the type well known in the networking arts. Delivery to thetuners 202 of the premises is then effected via normal RF transport(e.g., indigenous cable plant infrastructure). Alternatively, deliveryto the premises may utilize FTTx (e.g., FTTH, FTTC or the like) opticalfiber delivery.

In contrast, the architecture of FIG. 2e utilizes an RF domain outputfrom the SGDs 204 to one or more RF combiners 265, and then to therespective service groups 266.

In the embodiment of FIG. 2f , an RF output from the SGDs 204 isutilized (and one or more RF combiners 265, as in the embodiment of FIG.2e ); however, the two-way RF communications 267 and DOCSISfunctionality 268, 269 are removed from the SGD 204, and provided viaseparate functionality (e.g., through existing CMTS).

FIGS. 2g-2j illustrate various content and signal flows within thegeneralized architectures of FIGS. 2d-2f . The various components of theillustrated architecture include: (i) one or more receivers 274 whichprovide satellite acquisition; (ii) one or more encoders 275 thatconvert analog signals to digital; (iii) one or more dampers 276 whichconvert digital variable bitrate (VBR) signals to constant bitrate (CBR)or “clamped” signals; (iv) one or more MPEG overlay entities 277, whichprovide bulk graphics and video overlay of MPEG (e.g., EAS); (v) one ormore VOD servers 105 which provide CBR MPEG streaming engines for MoviesOn Demand (MOD) or On Demand (OD) content; (vi) one or more DPI servers272 which provide CBR MPEG streaming engines for advertisement and othersecondary content insertion; (viii) one or more splicers 278 that insertadvertisements and other secondary content into program streams; (ix)one or more network encryptors 279 or session encryptors 281 that applyencryption to digital signals; (x) one or more “bulk” statisticalmultiplexers 280 that optimize digital channel loading via statisticalmultiplexing processes; and (xi) one or more SGDs 204 as previouslydescribed, which are in the exemplary configuration TDM-to-FDMtransformers.

Specifically, FIG. 2g illustrates analog broadcast signal flow, from oneor more sources 270 and via a digital program insertion (DPI) server272. A bulk overlay (e.g., EAS) is applied to the unencrypted singleprogram transport stream (SPTS) multicast, and the resulting signalssent to the SGD 204 for conversion to the frequency domain as previouslydescribed.

FIG. 2h is a logical block diagram illustrating the signal flow for VODcontent delivery within one exemplary architecture of the network. Asshown, the content resident on the VOD server 105 is streamed as anunencrypted SPTS to a session encryptor 281 for encryption. Theencrypted content is then converted by the SGD 204 to the frequencydomain, and distributed as a unicast to the relevant service group fordelivery to the requesting CPE.

FIG. 2i is a logical block diagram illustrating the signal flow for VODwith “start-over” functionality within one exemplary architecture of thenetwork. As shown, the content is ingested from one or more sources, andthe DPI server 272 inserts advertisements or other secondary content toform an unencrypted SPTS multicast. This SPTS is provided to a scheduler282 (e.g., such as the exemplary Sectamus device of the Assigneehereof). The automated scheduler 282 provides pagination (i.e.,segmenting of the continuous incoming broadcast streams into programfiles) and implements business rules for the content and determineswhich programs will be passed to the VOD system and written to storage.The scheduler may also be configured to apply the appropriate metadatacontent (title, rating, starring actors, etc.) to the program as it isbeing prepared for “start-over” delivery. The VOD server then streamsthe SPTS unicast to the session encryptor 281 for encryption, and thenthe SGD 204 for transformation and delivery as a unicast.

FIG. 2j is a logical block diagram illustrating the signal flow forswitched (e.g., SDV multicast) content delivery within one exemplaryarchitecture of the network. As shown, the content is ingested from oneor more sources and converted to digital domain as required by theencoder 275, and clamp the VBR signal to a CBR using the clamper(s) 276.The DPI server 272 inserts advertisements or other secondary content toform an unencrypted SPTS multicast. The unencrypted SPTS multicast isthen provided to the bulk (network) encryptor 279, where it is encryptedand provided to the SGD 204 for transform and multicast distribution.

Spectrum Allocation—

FIG. 3 is a representation of one prior art RF spectrum 300. CurrentNorth American cable television frequency spans from 54 MHz to 1 GHz. Asshown, the prior art implementations intermix channel allocations acrossthe bandwidth using comb insertion filters, splicing, mixing, etc. Forexample, HSD 312, HD 306, SDV 310 and VOD 308 services are “shoehorned”into available channels. Certain higher bandwidth applications prefercontiguous and/or adjacent bandwidths. The highly heterogeneousallocations are difficult to modify; for example, changing theallocations for resources, or moving channels affects many otherchannels. Similarly, block up-conversion for narrowcast QAMs can furthercomplicate channel calculations; up-conversion requires adjacent 6 MHzslots in blocks of 2, 4, 8, 12, or 16.

In contrast to the prior art spectrum of FIG. 3, FIG. 4 illustratesseveral possible spectrum allocations according to the presentinvention, corresponding to different software configurations. Considera first software configuration 410, which has neatly aggregateddifferent content types together. As shown, analog channels 302, digitalchannels 304, High Definition (HD) channels 306, Video on Demand (VOD)channels 308, Switched Digital Video (SDV) 310, and High Speed Data(HSD) 312 are grouped together (the illustrated configuration issimplified for purposes of illustration).

A second software configuration 420 has a different spectrum allocationfrom the first spectrum. As shown, more channels are allocated for HD306, VOD 308, SDV 310, HSD 312, and analog channels 302 are reduced.

Similarly, a third software configuration 430 juggles the variousallocations arbitrarily (HD has been swapped with analog channels, VODand SDV have also been swapped). In fact, a myriad of possible softwareconfigurations can be used to control the appropriate networkutilization. Channel allocations can be dynamically reprogrammed toeasily accommodate on-the-fly block up-conversion, channel juggling, andchanges to service offerings.

In contrast to prior art network management, various embodiments of thepresent invention control spectrum allocation with softwareconfiguration. Changes to spectrum allocation are resolved in software(e.g., updating a configuration file, changing operational parameters,etc.). Similarly, embodiments of the present invention do not requireany rewiring or rerouting of hardware at the hub site or otherwise;instead, configuration changes are software updates that parameterizethe conversion from digital content to individual frequency channels.

Edge Device Apparatus—

FIG. 5 is a graphical representation of one exemplary implementation ofa full spectrum edge device 204 according to the invention. The device204 includes a network interface 502, a processor subsystem 504 and itsassociated storage 506, a programmable substrate 508, and a downstreaminterface 510 for delivering content to recipient devices (e.g., CPEs202). Each of these components is described in greater detailsubsequently herein.

The device 204 of FIG. 5 is merely representative of features andoperations of a full spectrum edge device, and design or configurationchanges necessary for other network technologies are readily appreciatedby those of ordinary skill given the present disclosure.

The illustrated device 204 can assume literally any form factor. Oneexemplary embodiment is adapted for rack use. Alternate embodiments maybe integrated in whole or part (e.g., on a common functional basis) withother devices if desired.

Network Interface—

In one embodiment, the network interface 502 of the edge deviceschedules and/or receives subscriber content for transmission. Thenetwork interface may queue data, receive streaming data, handlejust-in-time reception of content, etc. In one variant, the subscribercontent is received from one or more data sources via the networkinterface. The data sources may generate the content locally, oralternatively act as a gateway or intermediary from another distant orthird party source. Examples of such data sources may include othernetworked servers for Digitized Analog, Digital, Video-On-Demand (VOD),Switched Digital Video (SDV), High Speed Data (HSD), etc.

In the following discussions, a packet-switched network interface isdisclosed in detail. In alternative embodiments, the network interfacemay be circuit-switched. Packet-switched data delivery has unpredictablehops, and variable delays; however, packet-switched networks efficientlyallocate network bandwidth, and flexibly resolve network congestion. Incontrast to packet-switched networks, circuit-switched networks maintaindedicated connections of constant bit rate and constant delay betweennodes. Circuit-switched networks may also carry packetized data (e.g.,ATM with VPI/VCI). Circuit-switched networks are generally reliable, butalso generally less efficient. The tradeoffs and design considerationsfor circuit-switched and packet-switched networks are well understoodwithin the relevant arts; modifications to the present invention for usewith circuit-switched networks are well within the skill of the ordinaryartisan, given the contents of the present disclosure.

In the previously described exemplary embodiment of FIG. 2, the networkinterface 502 is based on a Gigabit Ethernet (Gig-E) interface. Gig-E isa packet-switched technology, i.e., blocks of data are sent and receivedvia a “cloud” of connections within a network. Each networked device isgiven a unique MAC (Medium Access Control) address, and routing isperformed on a hop-by-hop basis (MAC addresses are included in everydata packet to specify both the destination and the source of each datapacket). In Gig-E networks, data packets are encapsulated within a“frame”. The frame may also include physical layer components such as apreamble, and flow control characters.

The Gig-E interface receives content from multiple sources 208. Each ofthe content sources provides content in a time-multiplexed manner.Time-multiplexing refers to providing multiple sources of information ina time scheduled manner. For example, common embodiments use a roundrobin schedule, where each source takes turns on the connection. Thetime domain is divided into timeslots. Thus, during the first timeslot,the first source has a connection, etc. Time slots may be allocated on arecurrent, single shot, opportunistic, etc. basis. Various sources mayhave different levels of priority. Other time-multiplexing schemes arewell known throughout the related arts, and accordingly not describedfurther herein.

In some variants of the present invention, the network interface 502additionally comprises one or more buffer queues, suitable for bufferingdata delivery. In some implementations, the buffer is filled and thenconsumed; alternately, the buffer may be filled and consumedsimultaneously. Furthermore, in certain applications, the buffer may beoversized to provide additional overrun protection (i.e., rate ofconsumption out paces the rate of filling). Flow control may also beimposed by the interface (e.g., using pause frames or stop packets,throttling, etc.) where needed in order to control the flow of data fromone or more sources.

Generally, real-time streaming multimedia applications (such as video)may be highly sensitive to bit rates, and/or delay. Thus, in oneembodiment of the present invention, the network interface 502communicates Quality of Service (QoS) parameters with its data sources208, or other network management entity. QoS provides traffic managementpriorities to different applications, users, or data flows, or toguarantee a certain level of performance. QoS parameters may control bitrates, delay, jitter, packet dropping probability, bit error rates, etc.One exemplary scheme employs the well known RTP/RTCP (Real-TimeTransport Protocol/RTP Control Protocol) protocols for this QoSfunction, although it will be appreciated that other schemes andprotocols may be used with equal success.

In one embodiment, the network interface 502 is also coupled to anoptional processing subsystem 504, and programmable substrate 508; thecoupling enables network configuration and programming (e.g., devicecontrol) therefrom, as described in greater detail subsequently herein.

The network interface 502 can be configured to selectively connect toone or more external data content devices 208. In one exemplaryembodiment, the network interface can selectively couple to one or morebroadcast services, and one or more narrowcast services. In one variant,the connections are dynamically determined with a processing subsystem504 executing one or more business and/or operational optimizations. Inan alternate variant, the connections are remotely set via a centralizednetwork management entity. In yet another alternate variant, theconnections are hardcoded into a removable device, such as ahot-swappable card, computer readable memory media, etc.

In some embodiments of the edge device, the network interface 502 is awireless interface. For example, in one embodiment, the networkinterface is associated with the Worldwide Interoperability forMicrowave Access (WiMAX) transport; see IEEE Std. 802.16e-2005 entitled“IEEE STANDARD FOR LOCAL AND METROPOLITAN AREA NETWORKS—PART 16: AIRINTERFACE FOR FIXED AND MOBILE—BROADBAND WIRELESS ACCESS SYSTEMSAMENDMENT 2: PHYSICAL AND MEDIUM ACCESS CONTROL LAYERS FOR COMBINEDFIXED AND MOBILE OPERATION IN LICENSED BANDS”, and subsequent variantsthereof, including e.g., 802.16-2009, which are incorporated herein byreference in their entirety. In another variant, a millimeter wavesystem, WirelessHD, WiGIG, or satellite downlink is utilized. Wirelessembodiments may find particular use areas where cabling may be difficultor even impossible to support. For example, mobile embodiments (such asa cruise ship, train, or plane) may receive both live content viasatellite, and “canned” content (e.g., ship specific programming) foruse within a scaled-down version of the edge device (describedhereinafter).

Encryption of the network interface link is network-specific (e.g.,based on the platform, network/MSO, payload, etc.), and may be handledexternal to the device or alternately, internalized within theprocessing subsystem 504 (i.e., fixed encryption networks, etc.). Thus,some network interfaces may require additional encryption/decryptioncapabilities. In one exemplary embodiment, the full spectrum edge devicerelies on external devices for broadcast, common-tier, and session-basedencryption. In one such variant, encryption is handled with “bulkencryption”; i.e., the entire payload is encrypted by an encryptionengine. In other variants, encryption may be based on interface-specificconsiderations, thereby providing support for encryption protocolflexibility (e.g., legacy and future standards, external and internalencryption, etc.).

Furthermore, other embodiments may include additional pre-processing orpost-processing operations, whether on the edge device 204 oroff-device. For instance, excess resources (e.g., unused programmablesubstrate, idle processor time, etc.) of the edge device 204 can berepurposed to implement a wide range of miscellaneous tasks, includingfor example, encryption, decryption, encoding, decoding, transcoding,transrating, format conversion, upsampling, downsampling, etc.

Processor—

In some embodiments of the invention, a processor 504 and associatedstorage 506 is provided. The processor can execute software whichconfigures the programmable substrate 508 for full spectrum generation.In other embodiments, the programmable substrate is configured remotelyfor spectrum generation. In some circumstances, the programmablesubstrate may be configured at manufacture, and deployed in a“hardcoded” format. While dynamic and/or remote programming support isgenerally preferred for most implementations, it is appreciated thatcertain scenarios or constraints may render these features unsuitable orundesirable for use. For example, in closed-circuit operations, apre-constructed rack unit or board may be swapped or placed intoservice, without the benefit of external network administration, orassistance. Such closed implementations may be particularly useful insensitive security environments.

In one such variant, the processor 504 receives a pre-compiled binaryimage file for programming the programmable substrate 508. Thepre-compiled binary image files may be compiled by a networked entity,based on known configurations and device layouts. Pre-compiled binaryfiles are virtually impossible to tamper or reverse engineer; however,pre-compiled binary files are specific to the device; without safetyprecautions, an incorrect file can cause physical damage to devicecomponents. In contrast, other variants may provide metadata to theprocessor, enabling the processor to compile a binary image filesuitable for device specific programmable substrate configuration. Forexample, such metadata may include total bandwidth, channeldistribution, an allocation of services, etc. Metadata is significantlyeasier to distribute; however, compiling a binary image file is nottrivial, and requires a much more capable processor, and associatedsoftware.

In one embodiment, the processor 506 programs a non-volatile memory (notshown) with a binary image file for programming the programmablesubstrate 508. Non-volatile memories, such as FLASH, EEPROM, EPROM, etc.retain their contents without power. Non-volatile binary image storagemay be useful to accelerate start-up (e.g., after a power loss, orrestart, etc.), or for other applications such as hot-swap embodiments.Programming or “burning” a binary image to non-volatile memory is muchslower than directly programming the programmable substrate; however,once the image is burned into the substrate, the device can greatlyspeed up configuration. The non-volatile memory automatically configuresthe programmable substrate during power-up.

Alternatively, the processor 504 can program the programmable substrate508 directly. For example, programmable substrates which areLook-Up-Table (LUT) based can be “written” to (similar to a RandomAccess Memory (RAM)). Similarly, Digital Signal Processor basedsubstrates may be programmed by writing to its execution memory.Volatile memories, such as LUTs and RAMs, lose their contents when powercycled, and must be reprogrammed anew.

Alternative embodiments which are programmed remotely may similarly be“burned” or directly programmed. Existing solutions for remoteconfiguration of programmable substrates are well known in the art, andnot further described herein.

In another implementation of the present invention, a processor 504 andassociated storage 506 configures the network interface 502 dynamicallyto selectively receive data from one or more external data contentdevices 208. The connections are dynamically determined based on e.g.,one or more business and/or operational optimizations; for example, theprocessor may elect to maximize the number of profitable narrowcastservices, at the expense of broadcast services. Other profit orrevenue-maximizing algorithms are further discussed subsequently herein.

The processing subsystem 504 adds flexibility to the full spectrumgeneration apparatus 204, both in terms of content management, networkoperation, and other operational parameters. For example, in someembodiments, the processing subsystem 504 supports multiplexing of videoor other content (e.g., programs) using feed-back or feed-forwardinformation, as discussed in co-owned U.S. Pat. No. 7,602,820 issuedOct. 13, 2009 and entitled “APPARATUS AND METHODS FOR MULTI-STAGEMULTIPLEXING IN A NETWORK”, which is incorporated herein by reference inits entirety. Consider a cable network having a number of contentsources 208, a spectrum generation device 204, and a service groupcontaining a local hub. The edge device 204 negotiates with the localhub to reserve bandwidth for the local hub within the service group. Theprocessing subsystem 504 may receive and grant requests for bandwidthfor downstream use by the local hub. Thus, a portion of the frequencyspectrum output is kept in “pristine” condition, thereby allowing thelocal hub to insert content (e.g., adding a QAM subsequentlythereafter).

In another embodiment, the processing subsystem supports accessing data(such as video, audio or data files) over a network according todownload or “on demand” paradigms, as discussed in co-owned, andco-pending, U.S. patent application Ser. No. 11/258,229 filed on Oct.24, 2005 and entitled “METHOD AND APPARATUS FOR ON-DEMAND CONTENTTRANSMISSION AND CONTROL OVER NETWORKS”, which is incorporated herein byreference in its entirety. For example, a content distribution network(e.g., cable HFC) may be connected with a CSP (cellular serviceprovider) or wireless service provider (WSP). On-demand content may bedelivered via a “point-to-point” approach, where a session isestablished between a content receiving entity (such as a cellulartelephone) and a distributing entity's processing subsystem (e.g., thefull spectrum device 204). The processing subsystem 504 supports sessionestablishment (e.g., a SIP session), and data flow control usingprotocols and bandwidth typically used for (i) providing on-demandservices to subscribers within the cable network, and (ii) delivery andcontrol of streaming multimedia to client mobile devices.

In yet other systems, the processing subsystem of the edge device 204transparently and opportunistically utilizes bandwidth reclaimed afterremoval of null or “stuffing” data inserted into a program stream for,inter alia, producing constant-rate streams, as discussed in co-owned,and co-pending, U.S. patent application Ser. No. 11/291,328 filed onNov. 30, 2005 and entitled “APPARATUS AND METHODS FOR UTILIZING VARIABLERATE PROGRAM STREAMS IN A NETWORK”, which is incorporated herein byreference in its entirety. For example, in networks where bandwidth islargely variable and unpredictable, the processing subsystem 504 canactively detect “transient” bandwidth, and request additional content orbackfill local content to deliver secondary content elements.Additionally, the secondary content elements occupy the same QAMs whichalso carry the primary or program content, thereby allowing for tandemuse of existing QAMs.

Additionally, the processing subsystem 504 (where utilized) may utilizea “switched digital” approach to (i) deliver packetized content onlywhen requested, and (ii) selectively switch cable modems (CMs) or othersuch CPE to and from certain downstream channels (e.g., DOCSISQAM-modulated RF channels) based on switching algorithms, as discussedin co-owned, and co-pending, U.S. patent application Ser. No. 11/325,107filed on Jan. 3, 2006 and entitled “METHODS AND APPARATUS FOR EFFICIENTIP MULTICASTING IN A CONTENT-BASED NETWORK”, which is incorporatedherein by reference in its entirety. In one embodiment, the processingsubsystem executes algorithms for detecting and exploiting the fractionof the available program channels which is not in use; hence,intelligent and timely switching of individual subscribers (or groups ofsubscribers) can reduce the number of downstream channels that must beallocated to delivery of content.

Moreover, other embodiments of the processing subsystem 504 can executemanagement and control of electronic devices connected to a network, asdiscussed in co-owned, and co-pending, U.S. patent application Ser. No.11/363,577 filed on Feb. 27, 2006 and entitled “METHODS AND APPARATUSFOR SELECTING DIGITAL CODING/DECODING TECHNOLOGY FOR PROGRAMMING ANDDATA DELIVERY”, which is incorporated herein by reference in itsentirety. For instance, the processing subsystem may control hardwareand software functions/modules of different devices on the network toenable various capabilities and options, including conditional accesscapabilities, video coding or compression capabilities, encryptionschema, and network interfaces. Thus a full spectrum device (e.g., edgedevice) could support tailored conditional access, coding, encryption,and/or network interfaces for delivery of content to each particularclient device of its service group.

Yet other embodiments of the processing subsystem 504 of the edge devicecan maintain and analyze historical viewing or use information, asdiscussed in co-owned, and co-pending, U.S. patent application Ser. No.12/012,019 filed on Jan. 30, 2008 and entitled “METHODS AND APPARATUSFOR PREDICTIVE DELIVERY OF CONTENT OVER A NETWORK”, which isincorporated herein by reference in its entirety. Historical viewing anduse information collected by the processing subsystem can be used topredicatively request or cache content for “stuffing” bandwidth that isnot currently being consumed via consumer requests with programming thatis predictively selected.

Processing subsystems can also control network bandwidth utilization bydelivering to users only the minimum number of programs required byservice provider policies, as discussed in co-owned, and co-pending,U.S. patent application Ser. No. 11/881,034 filed on Jul. 24, 2007 andentitled “METHODS AND APPARATUS FOR FORMAT SELECTION FOR NETWORKOPTIMIZATION”, which is incorporated herein by reference in itsentirety. The flexibility of the content delivery could conceivablycause significant congestion during drastic changes in programmingconsumption; for example, bottlenecking at the full spectrum generationdevice 204. So-called “primetime” viewing typically comprises themaximum number of individual programs being delivered, as well as themaximum diversity of programs; the primetime demand for programmingtypically differs dramatically from the demand during early morningviewing, and also from that of other relatively high consumptionperiods. Consequently, in periods of excessive bottlenecking, theprocessing subsystem may be required to enforce minimum service providerpolicies.

Another “network friendly” policy executable within the processingsubsystem 504 includes tiered usage of: (i) a reclamation process; (ii)and overflow process; and (iii) a triage process, as discussed inco-owned, and co-pending, U.S. patent application Ser. No. 12/152,749filed on May 15, 2008 and entitled “METHODS AND APPARATUS FOR BANDWIDTHRECOVERY IN A NETWORK” (which claims the benefit of U.S. ProvisionalPatent Application No. 60/930,450 of the same title, filed on May 15,2007), which is incorporated herein by reference in its entirety. Forexample, the processing subsystem 504 can enforce graded or escalatingimpact based on the severity of the bandwidth deficit.

Still other variations of processing subsystems “intelligently” optimizecontent-based network operation based on, e.g., cost and/or revenueimplications in the context of “on-demand” video services, as discussedin co-owned, and co-pending, U.S. patent application Ser. No. 12/072,637filed on Feb. 26, 2008 and entitled “METHODS AND APPARATUS FORBUSINESS-BASED NETWORK RESOURCE ALLOCATION”, which is incorporatedherein by reference in its entirety. The processing subsystem candynamically evaluate and reallocate network assets based on, inter alia,the revenue and “cost” implications associated with various resourceallocation options. For example, the processing subsystem assesses thevarious implications of different possible resource allocations withinthe on-demand (OD) delivery paradigm (e.g., FOD, SVOD, HDVOD, etc.). Theprocessing subsystem 504 in one embodiment allocates/reallocates programstreams (such as according to one or more predetermined or dynamicallyvariable criteria) in order to continually optimize the revenue/profitversus resource cost equation.

Furthermore, commingling of video and data services can be optimizedwithin various aspects of the present invention. For example, theinvention can be used to boost utilization of a single QAM's capacity.Consider a DOCSIS 3.0 stream supporting up to 38.8 Mbps of payload; inone embodiment of the present invention, the underutilized portion canbe stuffed with additional data (e.g., 30 Mbps baseline “stuffed” tosupport an additional 8.8 Mbps). Techniques for “packing” unusedbandwidth are well known in the related arts, and include thosespecified in DOCSIS 3.0, and/or equivalent solutions used within DSMCCdata carousels. DSMCC supports a variety of communication models,including interactive transport control of audio and video streams in abi-directional environment such as a cable television VOD system.

More generally, however, those of ordinary skill in the related artswill recognize that allocated spectrum can be sub-divided into “slices”and apportioned to any number of users. Control channels can be used fordistributing relevant information to the users including, for example,addressing, permissions, etc.

Programmable Substrate—

In one aspect of the present invention, the programmable substrate 508of the device of FIG. 5 receives data from the network interface, andgenerates the entire spectrum for distribution to one or moresubscribers within the serviced group. In one embodiment, theprogrammable substrate receives a plurality of time-multiplexed contentdata streams as previously described, and converts the content to aplurality of frequency-multiplexed channels (e.g., QAMs).

Common examples of programmable substrates 508 include FPGAs (FieldProgrammable Gate Arrays), PLDs (Programmable Logic Devices), GALs(Generic Array Logic), etc. as well as hybrid reconfigurable DSPs(Digital Signal Processors), Fast DACs and other general purposeprocessing cores. In one exemplary embodiment, the programmablesubstrate 508 is configured to perform highly specialized and optimizedoperations (examples are described in greater detail hereinafter). Inless complex systems, a processor executing a generic instruction setmay be sufficient. Similarly, multiple parallelized operations maypreferentially be performed within dedicated logic; in contrast,serialized or unpredictably discontinuous operations can be moreefficiently handled in software. Thus, the complexity and configurationof the edge device is directly related to the nature of spectrumgeneration.

Furthermore, it is appreciated that rapid improvements in technology(e.g., parallel processing, compiler efficiency, fabrication geometries,etc.) and corresponding decreases in component cost may be aconsideration for future design construction. For example, it may bemore cost effective to use higher-cost reprogrammable substrates whichcan be frequently upgraded, as opposed to “one-shot” lower-costcomponents. In other examples, older and lower cost components andexisting software may be cheaper to maintain than porting existingsoftware to new platforms. Other implementations which trade cost forsubstrate capabilities are readily appreciated by those having ordinaryskill in the related arts, given the contents of the present disclosure.

In the exemplary embodiment, the programmable substrate comprises one ormore FPGAs. Architecturally, FPGAs are based on small memoryLook-Up-Tables (LUTs), which emulate logic (e.g., AND, NAND, OR, NOR,XOR, XNOR, etc.).

Consider the exemplary Look-Up-Table (LUT) 600 of FIG. 6, which has beenprogrammed to emulate a logical AND gate. In this example, the two (2)input LUTs comprises a memory device that can store four (4) values.During operation, the input operands 602 “address” the stored value;i.e., if the first operand is a logic one (1), and the second operand isa logic zero (0), then the value at address #10b is returned. Forexample, the logical AND operation can be emulated by programming theLUT with a zero (0) value in addresses #00b, #01b, and #10b, and a one(1) in address #1 lb. When both the first and second input operands area logical one (1), the LUT outputs a logical one (1); in all othercases, the LUT outputs a logical zero (0).

Typical implementations of LUTs are physically capable of emulating muchlarger and more complex logical operations. Historically, FPGAs werecomposed of four (4) input LUTs; however, recent advances in FPGAtechnologies have supported larger LUT sizes (e.g., eight (8) inputs,etc.). Moreover, as will be appreciated by those of ordinary skill inthe art, FPGA LUT construction provides programmability and flexibilityat the cost of gate efficiency. Static, stable, standardized, etc.portions of the apparatus could be more efficiently built usingtraditional Application Specific Integrated Circuit (ASIC) construction.Thus, in some embodiments, heterogeneous solutions may combineprogrammable logic with fixed logic gates and/or processor cores.

Other forms of programmable substrate may readily be substituted bythose having ordinary skill in the art, given the contents of thisdisclosure. For example, while FPGAs are LUT-based, other devices mayprogram arrays of fixed gate logic to create circuits. Such otherprogrammable substrates may include Complex Programmable Logic Devices(CPLDs), Programmable Logic Devices (PLDs), Programmable Array Logic(PAL), Generic Array Logic (GAL), etc.

In one exemplary embodiment of the present invention, the programmablesubstrate 508 is programmed to transform the content data into itsspectral equivalent. For instance, the programmable substrate isconfigured to execute a Fourier-type transform from the time domain tothe frequency domain.

The time and frequency domain are related to one another by the FourierTransform, and Inverse Fourier Transform. Common implementations ofFourier-type Transforms include Discrete Fourier Transforms (DFT), FastFourier Transforms (FFT), Discrete Hartley Transforms (DHT), DiscreteCosine Transform (DCT), Discrete Sine Transform (DST), etc. As usedherein, the term “transform” refers to, without limitation, anymathematical association (discrete or otherwise), useful for convertingdata from a first domain (such as time, frequency, etc.), to a seconddomain.

The Fourier Transform decomposes a signal into its frequency-domaincomponents, whereas the Inverse Fourier Transform performs the inversetransform; i.e., generates a time domain signal from itsfrequency-domain (spectral) components. One example of a particularlyuseful Fourier-type Transform is the Fast Fourier Transform (FFT) andthe Inverse Fast Fourier Transform (IFFT). The FFT/IFFT transforms arewell known within the art, and highly optimized hardware realizations ofthe FFT/IFFT transforms are used in many signal processing operations.Typical FFT/IFFT implementations exploit the similarity in the forwardand reverse directions to reuse hardware. Additionally, many solutionsare performed “in place” within memory; i.e., the transforms occurwithin a single memory buffer. FIG. 7 is a graphical depiction 700 ofthe relationship between the FFT, and the IFFT.

FIG. 8a is a graphical representation of frequency spectrum generationbased on one exemplary IFFT 800 implemented in accordance with oneembodiment of the present invention. A stream of time-multiplexed data802 is separated into its constituent elements 804. Each of the elementsis assigned to an appropriate frequency resource (e.g., QAM). Thisassignment may be for example based on a higher level mapping of contentstreams or programs to various frequency resources. Then, each elementis encoded as spectral coefficients 806 which are input to an IFFT. Forexample, as shown in FIG. 8a , a first constituent element 804A isassigned to QAM2, and a second constituent element 804B is assigned toQAM1. The IFFT generates the resultant spectrum 808, which is asummation of the products of the spectral coefficients multiplied bytheir corresponding frequency resource. As shown, if properly performed,the content 804 should have a distinct frequency band. The frequencydomain signal is passed to the downstream interface for transmission.

FIG. 8b is a graphical representation of frequency spectrum generationbased on a second exemplary embodiment of the present invention 850. Inthis embodiment, the content 804 within the multiplexed input isdemultiplexed into its individual constituent components as above, yetan OFDM (orthogonal frequency division multiplexing) operation (also anIFFT) is applied so as to multiplex the various components onto variousfrequency carriers at various times, thereby creating both time andfrequency diversity at the output of the edge device 204. Morespecifically, the content is spread over multiple time and frequencyresources, thereby minimizing the effects of burst interference, orfrequency specific interference (e.g., fading).

Furthermore, in such variants, the content 804 within the multiplexedinput further comprises multiple individual constituent components, as atime-multiplexed stream of multiple content elements. These multiplexedcomponents are then multiplexed onto various frequency carriers by theIFFT, thereby creating both time and frequency diversity for the alreadytime-diverse stream at the output of the edge device 204. In thisembodiment, the receiver (not shown) includes a demultiplexer at theoutput of the FFT, so as to demultiplex the recovered original datastream into its constituent content elements 804 if desired.Alternatively, a PID (process ID) or similar mechanism can be used topull packets from the multiplex without demultiplexing.

As appreciated in the digital audio and video broadcasting arts, thepresent invention can be further modified to support a wide range ofstatistical multiplexing methods to more efficiently provide audio orvideo services within a given fixed bandwidth. Consider a number ofservices or streams each of which has varying bitrates. In oneembodiment, a statistical multiplexer intelligently allocates bandwidthto each service based on, inter alia, Quality of Service (QoS)requirements such that prioritized services can have more bandwidth,than lower priority services. In fact, unlike prior art networks whichare configured and planned around relatively static channel usage, thepresent invention enables much more flexible and dynamic configurationof frequency resources, without maintenance or labor. For example, afull spectrum edge device can configure its programmable substrate toaccommodate changing bandwidth requirements.

Downstream Interface—

In one aspect of the present invention, the downstream interface 510receives the output of the programmable substrate 508, and transmits thesignal to one or more subscribers. In one embodiment, the downlinkinterface has a Radio Frequency (RF) output. In alternative embodiments,the signal is modulated to a direct laser output. In yet otheralternative embodiments, the signal may be modulated onto wiring or anyother modes of physical transference.

RF Output—

RF-based embodiments are generally constructed from oscillators,modulators, and amplifiers. Wireless variants may additionally includeone or more antennas. Generally, any method for transforming a digitalsignal to an analog waveform is sufficient. Laser embodiments areconstructed from a gain medium which converts energy to light. Commonimplementations of lasers utilize reflective surfaces and other opticalapparatus (lenses, mirrors, splitters, etc.) to further modify theemitted light.

Ideally, sufficiently large bandwidths are necessary to support allservices (analog, digital broadcast, VOD, SDV, HSD (e.g., DOCSIS1.0/3.0) and RF-Two-way, etc.). The aforementioned exemplary fullspectrum edge device generates a RF spectrum spanning from baseband to 1(one) GHz. In future implementations, spectrum generation can beexpanded beyond the current capabilities to support advancedtechnologies. For example, MoCA (Multimedia Over Coax Alliance) typecommunications are supported at higher frequencies (above 1 GHz). Infact, it will be recognized that current frequencies may constrained bythe physical media of the distribution plant (e.g., the attenuationcharacteristics of coaxial cable); future advances in materials, networktopologies, and/or methods can ostensibly support much higherfrequencies/rates.

The range is nominally sub-divided into 6 (six) MHz increments andquadrature-amplitude modulated (also referred to throughout as a “QAM”);other larger or smaller increments (e.g., 8 MHz) may be used as well.For example, as described in co-owned and co-pending U.S. patentapplication Ser. No. 11/013,671 filed Dec. 15, 2004 and entitled “METHODAND APPARATUS FOR WIDEBAND DISTRIBUTION OF CONTENT” and incorporated byreference in its entirety herein, describes support for wideband QAMshaving larger bandwidths (e.g., 8 (eight) MHz bandwidths, etc.).Moreover, an edge device could offer mixtures of bandwidths, e.g., 4MHz, 6 MHz, 8 MHz, etc. Additionally, even though the aforementionedincrements are 6 MHz wide, multiple increments can be bundled, to formlarger slots in blocks of 2, 4, 8, 12, 16, etc. (i.e., 12 MHz, 24 MHz,48 MHz, 72 MHz, 96 MHz, etc.).

It is appreciated that the spectrum described above may also includeprohibited frequency bands or buffers (e.g., guard bands) so as tomitigate, inter alia, inter-carrier or other types of interference. Asused herein the term “contiguous” refers both to cases where theindividual frequency bands or carriers are actually contiguous to others(i.e., no guard band(s)), or are contiguous but for one or moreintervening guard bands.

Still other limited capability variants could reproduce a smallerspectrum, containing only limited, or special engagement programming.For example, in low use rural areas or mobile applications (e.g., acruise liner, train, plane, etc.), a reduced-capability edge devicecould provide only limited channel selection to a few tuners. Similarly,such devices could be used in areas having significantly lessprogramming content. These reduced-capability variants could supportspectrums having a corresponding bandwidths e.g., 300 MHz bandwidth, 600MHz bandwidth, etc.

In yet other embodiments, the downstream interface may be wireless. Forexample, multiple WiMAX base stations may be established by the MSO orother content provider. One or more of the WiMAX stations arecoordinated full spectrum generation devices. Received content and/ordata are transmitted to the CPE (which may include simultaneousconstructive interference systems).

It can also be appreciated that the methods of the present invention maybe practiced using any configuration or combination of hardware,firmware, or software, and may be disposed within one or any number ofdifferent physical or logical entities. For example, the aforementionedprogrammable substrate functionality may take the form of one or morecomputer programs. Alternatively, such computer programs may have one ormore components distributed across various hardware environments at thesame or different locations, such as where a network process isdistributed across multiple platforms.

As yet another example, portions of the functionality may be rendered asa dedicated or application specific IC having code running thereon.Myriad different configurations for practicing the invention will berecognized by those of ordinary skill in the art provided the presentdisclosure.

Laser Output—

In another embodiment, the output of the edge device(s) comprises anoptical domain (e.g., coherent or Laser) signal. As previouslymentioned, laser embodiments are constructed from a gain medium whichconverts energy to light. Each bit stream (e.g., logical channel) isrepresented using a wavelength of light, which can be turned off-and-onindependently. Fiber optic lasers “tune” light by changing variouscharacteristics of the gain medium. For example, some “tuned” lasersadjust the size of the resonating cavity where the light is amplified.Heating or cooling the resonating cavity alters the resonating cavitiesrefractive index (resulting in shorter or longer wavelengths). Commonimplementations of distributed feedback (DFB) lasers use a coolingsystem to maintain a constant temperature in the resonating cavity.

In one embodiment, a wave-division multiplexing (WDM) approach is used,wherein the various program streams received at the edge device viae.g., the time-multiplexed transports are converted to an amplitude,which is modulated onto the wavelength channel (i.e., amplitudemodulation (AM)). For example, in one embodiment, the TDM signal isconverted with an IFFT to a FDM equivalent; each of the resultantspectral coefficients specifies the amplitude of correspondingwavelength of optical energy within for a laser transceiver. Unlike theprior art solutions which route the entire RF spectrum to a converterwhich converts the analog waveform to a laser equivalent; exemplaryembodiments can directly transform the data streams (TDM) to combinedoptical outputs (e.g., CWDM) within the same full spectrum edge device.

Furthermore, as appreciated by those skilled in the relevant arts, manyschemes could exist for the foregoing WDM combining. For example, in oneembodiment, the output of the edge device is provided to multipleinexpensive lasers, each of which generates only a subset (e.g., one) oflight wavelengths. In other embodiments, the outputs of multiple edgedevices can be coupled to multiple tunable lasers which can beconfigured to generate a wide range of spectrum. The different laseroutputs can be multiplexed together on one or more optical mediums. Tosupport legacy configurations, non-WDM approaches can also be used,wherein each discrete channel of information is carried over its ownfiber from source to sink. For example, a laser with optical modulatorreceives electrical domain signals, and converts them to the opticaldomain.

In one variant, each of the separate wavelengths of light (here in theC-band (1528 to 1603 nm), L-band (1570 to 1604 nm), or S-band (1450 to1500 nm) is generated by a distributed feedback (DFB) laser, andoptically combined with other wavelengths within an optical multiplexerfor carriage down a single fiber to one or more nodes, wherein thesignal is then distributed to CPEs via the prevailing distributionmedium (e.g., coaxial cable, CAT-5, optical fiber, wireless, etc.).Individual wavelengths are demultiplexed at the node via an opticaldemultiplexer. In one such implementation, each edge device 204comprises a plurality of DFBs and an optical combiner to physicallycombine the various (e.g., 2, 4, 8, 16, etc.) different wavelengths ontothe single fiber. This fiber is then used to service a given servicegroup within the network.

Alternatively, these components may be distributed further downstream inthe architecture, such as where the outputs from multiple edge devicesare optically combined.]

Supported Modulation Schemes—

In the exemplary embodiment of the full spectrum edge device, varioustypes of modulation schemes are supported, in order to make each edgedevice 204 “full service” (i.e., support each of the variedheterogeneous services now offered within the typical target network).

One such modulation type is QPSK (quadrature phase shift keying); thiswell known modulation supports e.g., “ALOHA”-based access protocols(e.g., pure ALOHA, slotted ALOHA, etc.), and DAVIC, for use inbroadcasting system information, or low data rate transfers. Morediscerning QAM (e.g., 64-QAM or 256-QAM) modulation is used e.g., tosupport digital encrypted broadcast functions including Encrypted MPTSand SPTS multicast and unicast, Switched Digital Video (encrypted SPTSmulticast), and VOD (encrypted SPTS unicast).

For example, DOCSIS services (e.g., DOCSIS 1.0, 3.0, etc.) utilize64-level or 256-level QAM (64-QAM or 256-QAM) for modulation ofdownstream data, and QPSK or 16-level QAM (16-QAM) is used for upstreammodulation. DOCSIS 2.0 and 3.0 also require that 32-QAM, 64-QAM and128-QAM be available for upstream data.

Accordingly, the exemplary configuration of the edge device programmablesubstrate includes multiple modulation logic in order to support thesevarious modulation types.

Methods—

Referring now to FIG. 9, one embodiment of the generalized process forspectrum generation in accordance with the present invention isdescribed. In one aspect, the spectrum generation entity 500 managesservice delivery between a number of sources and sinks (e.g., adding,removing, and/or modifying distribution paths). In one exemplaryembodiment, a single spectrum generation entity generates a fullspectrum signal encapsulating broadcast and narrowcast services. It isappreciated that in alternative variants, spectrum generation may beperformed by a number of devices or subsystems (e.g., multiple rackunits at a hubsite, etc.).

At step 902, the spectrum generation entity requests one or moreservices or content from a plurality of content sources 208. Typicalcable networks comprise a number of content sources including e.g.,Standard Definition (SD) content, High Definition (HD) content,Video-on-Demand (VOD) content, Switched Digital Video content, and HighSpeed Data (e.g., DOCSIS). However, content sources broadly include anysource of digital data such as for example a third party data source,mass storage devices (e.g., RAID system), file servers, etc.

In one embodiment of the present invention, the requests for one or moreservices are based on one or more requests received from a plurality ofserved Consumer Premises Equipment (CPE) 202. The CPE includes anyequipment in the “customers' premises” (or other locations, whetherlocal or remote to the distribution server) that can receive the outputsgenerated by the spectrum generation device. In alternative embodiments,the requests for one or more services are based on one or moredirectives received from an external network management entity.

In yet other embodiments, the requests for one or more services may beresponsively sent, based on conditions detected at another spectrumgeneration entity. For example, additional spectrum generation entitiesmay be used to supplement service offerings, or prevent noticeableservice blackout during device failure.

At step 904, the spectrum generation entity receives content fordelivery. Content may be scheduled for reception in segments, downloadedinto a queue, etc. In one variant the subscriber content is composed ofboth broadcast and narrowcast elements. Examples of such data sourcesincludes e.g., Standard Definition (SD) content, High Definition (HD)content, Video-on-Demand (VOD) content, Switched Digital Video content,and High Speed Data Over Cable Services Interface Specification (HSDDOCSIS), etc.

It is also appreciated that the spectrum or edge device may be “flooded”with all available programming (at least in the linear domain), akin toa prior art switched digital broadcast model. In the prior art model,the lack of any demand with the serviced subscriber group for a givenprogram allows that program to be “switched out” from delivery, therebyfreeing bandwidth for other programs or services which are beingactively utilized. When a “first” request for the switched-out contentis received, the switch responsively switches that program stream backinto the delivered set.

Similarly, one embodiment of the present invention floods the edgedevice with all relevant program streams, and the processor 504 and/orsubstrate 508 are configured to selectively include or remove thesestreams based on serviced user requests for the content. In one suchvariant, a given program stream within the time-multiplexed stream issimply allocated to a buffer or other mechanism which is not included inthe IFFT operation. Likewise, another stream can readily be mapped ontoa frequency resource in place of the removed stream.

In one exemplary embodiment, the content is received via a Time DomainMultiplexed (TDM) network. Alternate embodiments may receive theplurality of content via other multiplexing schemes (e.g., FDM, etc.).Furthermore, system design considerations may require the flexibility ofpacket-switched delivery, or alternately, the bandwidth guarantees ofcircuit-switched delivery. Additionally, network content delivery mayfurther include capabilities and support for Quality-of-Service (QoS)parameters. QoS parameters support resource reservation controlmechanisms and may, inter alia, provide different priorities todifferent content data, or guarantee a minimum delivery rate. Consistentspectrum generation may require guarantees for consistent bit rates,delays, jitter, packet loss, bit error rates, etc. Real-time streamingmultimedia applications often require fixed data rates, and are delaysensitive.

In one aspect of the present invention, the content data can be flexiblysourced from a wide variety of devices. In one embodiment, the contentdata is generically formatted in accordance with one or more broadcastservices, and/or one or more narrowcast services. Alternatively, thecontent data may be specific to a particular service, and provided viaspecialized or proprietary formats. In certain embodiments, narrowcastdata content can include user-centric and/or user-specified content(various examples for narrowcast user content are described in greaterdetail herein, see discussion of On Demand Services) as well as targetedsecondary content.

In one variant, the content data is dynamically included based on one ormore business optimizations (e.g., maximize narrowcast service, maximizesubscriber coverage, etc.). In other variants, the content data may bedynamically included based on one or more network considerations (e.g.,robust service coverage, service recovery, etc.). In yet other variants,the content data may be selected based on one or more apparatusconsiderations (e.g., device limitations, subscriber CPE limitations,etc.). Such considerations may also be remotely handled via acentralized network management entity.

The plurality of data content may be received from one or moreencryption devices, or “in the clear” (unencrypted) from one or moresource content devices. Still other variants may support encryption fora portion of the received streams (e.g., to support mixtures ofexternally encrypted and unencrypted sources, etc.).

At step 906, the spectrum generation device transforms the plurality ofcontent to a full spectrum format. The received data content isorganized, assigned, or collated into a number of channels for transfer.In one embodiment, one stream of data content (which may include one ormore program streams) is assigned to a channel suitable for generating 6(six) MHz of bandwidth. Such organization may include filling a suitablysized buffer memory for spectrum conversion. In some variants, largerchannels can be created by aggregating 2, 4, 8, 12, 16, etc. buffermemories (content streams) together.

In yet other variants, variably sized channels may be created byproviding a variably sized memory buffer, which can be dynamicallychanged. Still other variants may provide “padding” to support spectrumgeneration without content (such as may be useful when rolling out newfeatures, or removing old features, etc.).

Additionally, in some implementations, the channel data is collatedfirst (e.g., as stored within memories), and then assigned to a spectrumresource. Multiple stage processes can add additional data deliveryflexibility, at increased complexity. For example, in one embodiment,the channels may be further organized based on one or more optimizationprocesses (e.g., so as to avoid bandwidth constraints, or achieve otheroperational goals). In other embodiments, the channels may be organizedbased on a coherent standard or policy deployed on a network-wide basis.

Similarly, in yet other embodiments, the channels may be furtherorganized flexibly within a certain range. For example, various portionsof the spectrum may be allocated for legacy devices (e.g., analog anddigital standard definition service), whereas other portions of thespectrum may be restricted for specific users (e.g., to support variousnarrowcast options).

At step 908, the spectrum generation device transmits the transformed(time domain) content for reception by the plurality of sinks, such assubscriber CPE 106. In one exemplary Radio Frequency (RF) embodiment,transmission of the frequency channels includes conversion from digitalsamples to an analog baseband waveform, and frequency mixing fortransmission. In alternate embodiments, direct laser transmission of thechannels includes conversion from digital samples to an optical waveformfor transmission via a fiber optic cable.

Referring now to FIG. 9a , one exemplary implementation of thegeneralized method of FIG. 9 is illustrated.

As shown, the method 950 comprises the edge device 204 first receiving atime division multiplexed stream of content from its Gig-E interface(step 952). For instance, the stream may comprise several multiplexedprogram streams collectively forming a packet stream encapsulated in anappropriate protocol. Since a packet-switched delivery network isutilized, it is feasible that some packets may arrive out-of-order, andhence may be buffered and reordered upon receipt.

Next, per step 954, the received stream is demultiplexed, such as bypacket identifiers 30 that associate each packet with a particularstream. The individual streams demultiplexed from the parent stream arethen individually buffered (step 956), and allocated to particularfrequency resources per step 958. For example, as shown in FIGS. 8a and8b , various program streams may be mapped to one or more RF outputchannels (e.g., QAMs), including: (i) one program stream per QAM; (ii)multiple streams per QAM; and (iii) multiple QAMs per stream (e.g.,using the aforementioned wideband tuner).

Next, per step 960, the edge device transforms the individual programstreams into a full-spectrum representation of the input data. Forexample, in one embodiment, the input bitstream for each individualprogram stream is allocated to an individual frequency band orsubcarrier using an IFFT. Alternatively, a bitstream may be allocatedacross multiple different carriers (akin to OFDM), thereby providingboth time and frequency diversity if desired.

Lastly, per step 962, the data output from the IFFT operation isconverted to the analog domain (e.g., using a D/A converter),upconverted as required, and transmitted over the frequency spectrumeffectively as a wideband RF signal.

Example Operation—

The following scenarios illustrate the operational and other benefits ofone or more aspects of the present invention. Specifically, similarfunctions implemented within an extant cable distribution system usingprior art solutions required extensive capital expenditure, andextensive maintenance. In contrast, the present invention quickly andefficiently provides deployments of improved functionality in asubstantially seamless fashion.

Analog Reclamation—

As previously described, the cable spectrum may be composed of analogchannels, digital channels, High Definition (HD) channels,video-on-demand (VOD) channels, switched digital video (SDV) and highspeed data (HSD). Efforts to replace less efficient analog channel usagewith digital counterparts are currently under both federal andcommercial consideration. Prior art networks are both difficult tomaintain, and upgrade; the restructuring of channel structure is anexpensive and onerous task requiring significant amounts of capitaloutlay, and rewiring.

FIG. 10 illustrates one possible allocation 1000 of radio resourcesallocated to various services provided by a cable network provider. Thecable spectrum is composed of QAMs which are allocated to analogchannels 302, digital channels 304, High Definition (HD) channels 306,video-on-demand (VOD) channels 308, switched digital video (SDV) 310 andhigh speed data (HSD) 312, etc. The relative proportion of these variouscontent types are based on business considerations; as previouslymentioned. Narrowcast services such as HD, VOD, and SDV services areconsiderably more profitable; however, customers demand both breadth andlegacy compatibility offered by analog and digital channels.

FIG. 10 illustrates a second spectrum allocation 1050, which isrepresentative of current and future planned efforts to replace lessefficient analog channel usage with digital counterparts, whileexpanding more profitable narrowcast offerings.

The previously described spectrum generation entity can accommodateanalog reclamation (or any spectrum allocation changes) by reprogrammingthe network interface to receive data from new content sources, and areconfiguration of the output frequency channel locations. Instead ofreceiving the current allocation of analog services, the spectrum devicecan be programmed to receive content data from another networked contentsource. Similarly, channel structure can be changed to back-fill thereclaimed spectrum. New digital content can be addressed with newparameters for connecting to content servers, and channel assignments.Thus, various embodiments of the present invention can advantageouslyconfigure networks (in compliance with federal analog reclamationefforts) remotely, entirely in firmware or software, and virtuallyinstantly.

On Demand Services—

The present invention provides previously unattainable degrees offreedom for allocating between broadcast and narrowcast capabilities.This includes instantiation of user-specific narrowcast or unicastchannels for delivery of on-demand content. For example, “entitlement”based content data control is provided to a CPE via an on-demandsession, if the CPE or subscriber is entitled to the content. In oneembodiment, this is accomplished via the methods and apparatus disclosedin co-owned, co-pending U.S. patent application Ser. No. 12/536,724filed on Aug. 6, 2009 and entitled “SYSTEM AND METHOD FOR MANAGINGENTITLEMENTS TO DATA OVER A NETWORK”, incorporated herein by referencein its entirety. As discussed therein, in one embodiment, a request forcontent is received from the CPE at an entity (e.g., headend server) ofthe content and data distribution network. The network entity obtainsinformation identifying the user account (such as subscriberidentification number, account number, etc.), and uses this informationto request entitlements from an entitlements server (also located at theheadend in one embodiment). Based on the results returned from theentitlements server, the network entity either grants or denies therequest. The entitlements server accesses subscription information in asubscriber database to obtain sufficient information to determine theentitlements of the subscriber. When the requesting user is determinedto be entitled, the content (e.g., movie) can be provided to thespectrum generation device 204 for transmission via a limited engagementchannel that is instantiated for that user only. The present inventioncan thus temporarily create a limited engagement channel specific to theentitled CPE or subscriber only. At the conclusion of the delivery, theresources are no longer used, and may be readily reabsorbed into thespectrum budget.

Switched Digital Video (SDV)—

As another example, the edge device 204 of the invention can be disposedat a hubsite within a network, and operate according to an SDV paradigm.As previously described, traditional SDV floods the hubsite switch withall of the available programming; delivery of each program streamdownstream however is predicated upon one or more users watching a givenstream. When no users within the serviced group are watching a givenprogram, that program is switched out from downstream delivery, and thebandwidth that was being used to deliver it reclaimed.

Similarly, in the context of the present invention, the edge device 204may act as a switch, being controlled either remotely or by a localprocess which determines whether any subscribers have selected a givenprogram stream, and if not, remove this stream from delivery, such as by(i) simply not demultiplexing it from the incoming multiplexed contentstream; (ii) demultiplexing it but discarding the packets; or (iii)causing an upstream entity to remove it from the received multiplexedstream. Advantageously, however, the edge device 204 can also reallocatereclaimed spectrum for use in the same or other services (e.g., for aVOD session).

Passive Optical Networking (PON)—

In yet another example, the edge device 204 of the present invention cansupport yet other physical mediums and protocols. For example, in oneembodiment, the output of the full spectrum generation device may coupledirectly to a Passive Optical Network (PON) architecture (e.g., Ethernetover PON, or EPON). A typical PON is a point-to-multipoint,fiber-to-premises network architecture where unpowered optical splittersare multiplexed over a single optical fiber to serve multiple premises.For example, a full spectrum device that acting as an optical lineterminal (OLT) can transmit data to a number of optical network unit(ONU) CPEs. Yet other fiber optic distribution schemes may be readilyimplemented by ones of ordinary skill in the related arts given thepresent disclosure.

Business Models and “Rules” Engine—

In another aspect of the invention, one or more computer programsrunning on the processor 506 of the full spectrum apparatus 204 includesa so-called “rules” engine. This engine comprises, in an exemplaryembodiment, one or more software routines adapted to control theoperation of the apparatus in order to achieve one or more goalsrelating to operations or business (e.g., profit). Included within theseareas are network optimization and reliability goals, increasedmaintenance intervals, increased subscriber or user satisfaction,increased subscription base, higher revenue or profit (e.g., fromincreased advertising revenues), more subscriber “views” of givencontent, higher data download speed, increased bandwidth andresponsiveness to changing demands for bandwidth, reduction of unduechannel replication, and so forth.

These rules engine may comprise a separate entity or process, and mayalso be fully integrated within other processing entities, andcontrolled via e.g., a GUI displayed at a central network managementfacility, coupled via the network interface 502. In effect, the rulesengine comprises a supervisory entity which monitors and selectivelycontrols the operation of the spectrum generation device(s) at a higherlevel, so as to implement desired operational or business rules.

For example, the central network entity may invoke certain operationalprotocols or decision processes based on, inter alia, information orrequests received from the service group, conditions existing within thenetwork, demographic data, geographic data, user preferences, etc.However, these processes may not always be compatible with higher-levelbusiness or operational goals, such as maximizing profit or systemreliability. Hence, when imposed, the business/operational rules can beused to dynamically (or manually) control the operation of the fullspectrum apparatus 204. The rules may be, e.g., operational orbusiness-oriented in nature, and may also be applied selectively interms of time of day, duration, specific local areas, or even at theindividual user level.

For example, when sufficient bandwidth is present, the apparatus maydeliver narrowcast programming to optimize programming revenues.However, during instances of increased demand on the network, narrowcastprogramming may be greatly limited. In other words, as bandwidth demandincreases, lower-revenue narrowcast programming may be pruned out.Similarly, the central network authority can balance between targetednarrowcasting, and service coverage. Highly targeted narrowcast servicesare generally tailored to small coverage areas; thus as a service groupdiminishes in size, the proportion of targeted narrowcast services canincrease (and vice versa). Dynamic adjustment of narrowcast relevancycan greatly improve network profitability. These features are readilyleveraged within the edge device 204 of the invention due to its abilityto be almost instantaneously remotely reprogrammed to adjust is spectraloutput

Additionally, the benefits of remote monitoring, configuration andprovisioning capability enable greater flexibility in, inter alia, (i)troubleshooting and repairing faults within the content deliverynetwork; and (ii) changing or reconfiguring content delivery within thecontent delivery network. The reduced maintenance and upgrade costs havetangible value, as realized in both saved labor costs, and reducedinfrastructure investments.

Many other approaches and combinations of various operational andbusiness paradigms are envisaged consistent with the invention, as willbe recognized by those of ordinary skill when provided this disclosure.

It will be recognized that while certain aspects of the invention aredescribed in terms of a specific sequence of steps of a method, thesedescriptions are only illustrative of the broader methods of theinvention, and may be modified as required by the particularapplication. Certain steps may be rendered unnecessary or optional undercertain circumstances. Additionally, certain steps or functionality maybe added to the disclosed embodiments, or the order of performance oftwo or more steps permuted. All such variations are considered to beencompassed within the invention disclosed and claimed herein.

While the above detailed description has shown, described, and pointedout novel features of the invention as applied to various embodiments,it will be understood that various omissions, substitutions, and changesin the form and details of the device or process illustrated may be madeby those skilled in the art without departing from the invention. Theforegoing description is of the best mode presently contemplated ofcarrying out the invention. This description is in no way meant to belimiting, but rather should be taken as illustrative of the generalprinciples of the invention. The scope of the invention should bedetermined with reference to the claims.

What is claimed is: 1.-25. (canceled)
 26. A method of providingon-demand content to a user of a content distribution network, themethod comprising: receiving a request from a user for a digital contentelement; accessing the digital content element at an on-demand server;transmitting the accessed digital content element as part of a singleprogram transport stream (SPTS) to a transformation device;transforming, at the transformation device, the received digital contentelement to one or more time domain signals using digital domainprocessing; and transmitting the transformed signals to the user overone or more radio frequency carriers.
 27. The method of claim 26,wherein the digital content element carried in the SPTS is unencrypted,and the method further comprises encrypting the digital content elementbefore said act of transforming is performed.
 28. The method of claim26, further comprising converting the transformed digital contentelement to the analog domain before said transmitting to the user. 29.The method of claim 26, wherein said transmitting the digital contentelement as part of the SPTS comprises transmitting over a high-capacitypacketized backbone to the transformation device, the transformationdevice being disposed at a hub site of the network.
 30. The method ofclaim 26, wherein said digital domain processing comprises an inverseFast Fourier Transform (IFFT).
 31. The method of claim 26, wherein saidplurality of users are associated with a common service group withinsaid network.
 32. The method of claim 26, wherein said transformationdevice is substantially remotely reprogrammable, and said method furthercomprises dynamically changing an allocation of said transformed digitalcontent element to said one or more frequency carriers remotely.
 33. Themethod of claim 26, further comprising dynamically inserting one or moresecondary content elements into said digital content element before saidtransformation.
 34. The method of claim 26, wherein said SPTS comprisesa unicast SPTS, and said method further comprises: providing the digitalcontent element to a scheduler apparatus via a multicast SPTS, thescheduler apparatus configured to segment a plurality of program streamsinto a plurality of files; selecting one or more of said plurality offiles corresponding to the digital content element to be utilized by theon-demand server; and causing storage of the selected one or more fileson a storage apparatus associated with the on-demand server, said storedone or more files subsequently being used to form at least a portion ofsaid unicast SPTS.
 35. The method of claim 34, wherein said schedulerapparatus is configured to apply metadata content to the selected one ormore files prior to said storage.
 36. The method of claim 34, whereinthe selected one or more files corresponding to the digital contentelement carried in the unicast SPTS is/are unencrypted, and the methodfurther comprises encrypting the selected one or more files before saidact of transforming is performed.
 37. A method of providing on-demandcontent to a user of a content distribution network, the on-demandcontent having a broadcast-related start time associated therewith, themethod comprising: receiving a broadcast containing the digital contentelement as part thereof; processing at least a portion of the broadcastto obtain the digital content element for storage on a storage deviceassociated with an on-demand server; receiving a request from a user fora digital content element, the request originated after the start timeand causing creation of a session for that user; accessing the digitalcontent element at the storage device; transmitting the accessed digitalcontent element as part of a unicast single program transport stream(SPTS) to a transformation device; transforming, at the transformationdevice, the received digital content element to one or more time domainsignals using digital domain processing; and transmitting thetransformed signals to the user over one or more radio frequencycarriers, the transmitting commencing after the start time and thereceiving a request.
 38. A network apparatus configured to delivercontent from an on-demand digital content source to at least one userassociated with a content distribution network, said network apparatuscomprising: a first interface configured to access the on-demand digitalcontent source, the on-demand digital content source in communicationwith said content distribution network; a storage apparatus in datacommunication with the first interface and configured to at leasttemporarily store at least an accessed digital content element obtainedfrom said digital content source; and a remotely reprogrammabletransformation device configured to: receive said accessed digitalcontent element as part of a unicast single-program transport stream(SPTS); transform said digital content element from one or more timedomain signals to one or more time domain signals via digital domainprocessing; and a second interface configured to transmit saidtransformed one or more time domain signals to said at least one userover at least one radio frequency carrier.
 39. The apparatus of claim38, wherein said at least one radio frequency carrier comprises at leastone QAM-modulated channel, and said digital domain processing comprisesan inverse Fast Fourier Transform (IFFT).
 40. The apparatus of claim 38,wherein said first interface comprises an interface to a gigabitEthernet network, and said second interface comprises an interface tosubstantially circuit switched frequency distribution network.
 41. Theapparatus of claim 38, wherein said transformation device is disposed ata hubsite of a content distribution network and away from a core of saidcontent distribution network.
 42. A network apparatus configured todeliver content from a digital content source to at least one userassociated with a content distribution network via switched digitaldelivery, said network apparatus comprising: a first interfaceconfigured to access the digital content source to obtain a variablebitrate (VBR) digital content element, the digital content source incommunication with said content distribution network; computerized logicapparatus in data communication with the first interface and configuredto clamp the accessed VBR digital content element so as to produce acorresponding constant bitrate (CBR) digital content element; secondcomputerized logic apparatus in data communication with the firstcomputerized logic and configured to encrypt at least a portion of theCBR digital content element to produce an encrypted CBR digital contentelement; and a remotely reprogrammable transformation device in datacommunication with at least the second logic and configured to: receivesaid encrypted CBR digital content element as part of a multicastsingle-program transport stream (SPTS) being distributed to the remotelyprogrammable transformation device and a plurality of othercorresponding remotely reprogrammable transformation devices within saidnetwork; transform said encrypted CBR digital content element from afirst domain to a second, different domain via digital domainprocessing; and a second interface configured to transmit saidtransformed one or more second domain content to a plurality of usersover at least one radio frequency carrier and via a switched deliveryapparatus, the switched delivery apparatus comprising logic configuredto selectively switch in and switch out said encrypted CBR digitalcontent element from delivery based at least on a presence or absence ofa user being tuned to the at least one radio frequency carrier.
 43. Theapparatus of claim 42, wherein said at least one radio frequency carriercomprises a plurality of radio frequency carriers, and said transmissioncomprises transmission over different ones of the plurality of carriersas a function of time so as to provide both frequency and timediversity.
 44. The method of claim 26, wherein said at least one radiofrequency carrier comprises a plurality of radio frequency carriers, andsaid transmitting comprises transmitting over different ones of theplurality of carriers as a function of time so as to provide bothfrequency and time diversity.
 45. The method of claim 37, wherein saidone or more radio frequency carriers comprise a plurality of radiofrequency carriers, and said transmitting comprises transmitting overdifferent ones of the plurality of carriers as a function of time so asto provide both frequency and time diversity.